FS-File system
A file system is a hierarchical tree structure of files and directories. Some tasks are performed more efficiently on a file system than on each directory within the file system. For example, you can back up, move, or secure an entire file system.
File systems are associated with devices (logical volumes) represented by special files in /dev. When a file system is mounted, the logical volume and its contents are connected to a directory in the hierarchical tree structure. You can access both local and remote file systems using the mount command.
AIX supports these file system types:
JFS Journaled File System which exists within a Logical Volume on disk
JFS2 Enhanced Journaled File System which exists within a Logical Volume on disk
CDRFS CD-ROM File System on a Compact Disc
NFS Network File System accessed across a network
UDF Universal Disk Format (DVD ROM media)
GPFS General Parallel Filesystem
SMBFS Server Message Block Filesystem (cifs_fs, samba share)
All of the information about the file system is centralized in the /etc/filesystems file. Most of the file system maintenance commands take their defaults from this file. The file is organized into stanza names that are file system names and contents that are attribute-value pairs specifying characteristics of the file system.
/tmp: <-- names the directory where the file system is normally mounted
dev = /dev/hd3 <-- for local mounts identifies the block special file where the file system reside
for remote mounts, it identifies the file or directory to be mounted
vfs = jfs2 <-- specifies the type of mount. For example, vfs=nfs
log = /dev/hd8 <-- full path name of the filesystem logging logical volume (only for jfs and jfs2)
mount = automatic <-- used by the mount command to determine whether this file system should be mounted by default
type = nas <-- several file systems can be mounted by giving the value as an argument to the -t flag (mount -t nas)
check = false <-- used by the fsck command to determine the default file systems to be checked
vol = /tmp <-- used by the mkfs command when initiating the label on a new file system
free = false <-- it is there because of unix traditions only (It is totally ignored by any and all AIX commands)
(df command in traditional UNIX would use it to determine which file systems to report)
For the option mount, these are valid entries: automatic, true, false, removable, and readonly:
automatic fs is to be mounted at boot; this is usually used for system-defined file systems.
true mount all is allowed to mount this file system.
false mount will only occur when the file system is specified as an argument to the mount command, or the type is used for mount.
The asterisk (*) is the comment character used in the /etc/filesystems file.
To remove a file system data from /etc/filesystems: imfs -x -l <lvname>
System-Created File Systems in AIX
The six standard file systems in AIX Versions 5 and higher are /, /home, /usr, /proc, /tmp, and /var. Each of these file systems is always associated with a logical volume name:
Logical Volume File System or Description
------------------------------------------------------
hd1 /home (users' home dir)
hd2 /usr (operating system commands, libraries and application programs)
hd3 /tmp (temporary space for all users)
hd4 / (critical files for system operations, programs that complete the boot process)
hd5 <boot logical volume>
hd6 <primary paging space>
hd8 <primary JFS or JFS2 log>
hd9var /var (variable spool and log files)
hd10opt /opt (freeware programs)
/proc /proc (pseudo fs kept in memory to support threads)
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Superblock
In a JFS, the superblock is the first addressable block (and a backup at the thirty-first addressable block) on a file system. It is 4096 bytes in size. The superblock is very important because a file system cannot be mounted if the superblock is corrupted. This is why there is a secondary or backup superblock at block 31. The superblock contains the following: size of the filesystem, number of datablocks in the fs, state of the fs...
# dd count=1 bs=4k skip=31 seek=1 if=/dev/hd4 of=/dev/hd4 <--this will restore the superblock from block #31
# fsck -p <fs> <--this will copy also the superblock from #31
# dumpfs /usr <--shows the superblock, i-node map, and disk map information
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i-node (index node)
A file system has a fixed number of i-nodes that are located following the superblock. i-nodes contain information about files, including the location of the data on the disk. They contain all of the identifying information about files (file type, size, permissions, user/group/owner, create/modification and last access dates) except for the file name, which is stored in the directory, and the contents of the file, which are stored in the data blocks. Each file or directory has an i-node associated with it. AIX reserves a number of i-nodes for files and directories every time a file system is created, and if all the available inodes are used, no more files can be created, even if the fs has free space.
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jfslog
AIX uses a journaled file system, meaning that certain i-node information is stored in a transaction log during writes. Its real value is in maintaining the integrity of the file system. Journaled file systems enable faster system reboots after system crashes. Each volume group has a jfslog file that is automatically created when the first file system is created in that volume group. The jfslog ensures the integrity of a file system by immediately writing all meta-data information to itself. Meta-data is information about the file system, such as changes to the i-nodes and the free lists. The jfslog keeps track of what is supposed to happen to the file system and whether it gets done. You are allowed to have a separate log for each filesystem.
(If a jfslog has been created manually, the logform command should be used to activate it as the jfslog for that vg.)
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Special or device files
A special file, sometimes called device file is associated with a particular hw device or other resource of the computer system. AIX uses them to provide file I/O access to character and block device drivers. Special files are distinguished from other files by having a "c" or "b" stored in the i-nodes, and they are located under the /dev directory. Character and block I/O requests are performed by issuing a read or write request on the device file:
- Character device file: Character devices (tape drives, tty devices) are capable of doing sequential I/O.
- Block device file: Block devices can only do random I/O, such as disk devices.
mknod: creates new special files (i-node and the file type (c or b) sould be set), major minor numbers will be written into the i-node
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Directories
The directory entry contains an index number associated with the file's i-node, the file name....
Every well formed directory contains the entries: . and ..
-.: points to the i-node for the directory itself
-..: points to the i-node for the parent directory
Because directory entries contain file names paired with i-nodes, every directory entry is a link.
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Links
Links are connection between a file name and an i-node. The i-node number actually identifies the file not the filename. By using links, any i-node or file can be known by many different names.
-hard link: Hard links can be created only between files that are in the same fs.
(when the last hard link is removed , the i-node and its data are deleted)
# ls -li: (bello is a hard link, and link count 2 shows it)
4 -rw-r--r-- 2 root system 0 Jul 8 23:27 bello
-symbolic link: Allow access to data in other filesystems from a new filename.
# ls -li: (bello is a sym. link, and the first character "l" shows this)
lrwxrwxrwx 1 root system 15 Jul 8 23:30 bello -> /test_fs1/hello
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NameFS (Name File System)
A NameFS is a pseudo-file system that lets you access a directory through two different path names. With a NameFS you can create a second path and you don't have to change permissions, copy, move, rename or even touch the original file system.
You could use a Name File System to set up a directory with:
-an alternate path (so it’s like a shortcut)
-different permissions (e.g. when some applications or users should have read-only access)
-other mount attributes such as Direct I/O (dio) or Concurrent I/O (cio)
How to setup NameFS:
1. mkdir -p /shortcut <--create a dir, which will be the mount point for the new Name file System
2.:
mount -v namefs /some/long/path /shortcut <--with this you got access to the files via 2 paths
mount -v namefs -o ro /data/report /data_reports <--with this you can make a read only mount of a dir
mount -v namefs -o cio /db2/W01/redo /deb2redo <--with this you can mount a dir with CIO to improve I/O
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crfs ... creates a file system (crfs creates lv as well; mkfs will create an fs over an already created lv)
crfs -v jfs2 -d W01origlogAlv -m /oracle/W01/origlogA -A yes -p rw -a options=cio -a agblksize=512
mount displays information about all the currently mounted file systems
mount dir_name mount the file system according to the entry in /etc/filesystems
mount lv_name dir_name mount the file system to another lv than in /etc/filesystems
umount dir_name umount the filesystem
mount -a or mount -all mounts all the file systems at one time
lsfs displays the characteristics of file systems
lsfs -q more detailed info about the fs (lv size...) (it queries the superblock)
(-v: list filesytems belonging to given fs type (jfs2, nfs); -u: lists filesystems in the given mount group)
rmfs /test removes a file system
rmfs -r /test removes the mount point also
chfs -a size=+5G /shadowtemp it will increase by 5G the fs (-5G can be used as well, or 5G will set tthe size of the fs to 5GB)
(if fs was reduced but space is not freed up defragfs could help)
chfs -a options='rw' /shadow shows with lsfs rw (I think rw is the deafault anyway)
imfs -x -l <lvname> remove a file system data from /etc/filesystems
fsck checks file system consistency (should not run on a mounted file system)
defragfs /home improves or reports the status of contiguous space within a file system
ls -ldi <dir> shows inode number in the first column
istat /etc/passwd display information regarding a particular inode (last updated, modified, accessed)
(update: change in the inode (file name, owner...); modified: change in the content of the file or dir)
df monitor file system growth
du dir_name (disk usage), to find which files are taking up the most space
du -sm * | sort -rn | head shows every dir size in MB (du -sk * the same in KB), the first 10 largest
skulker cleans up file systems by removing unwanted or obsolete files
fileplace <filename> displays the placement of file blocks within logical or physical volumes, it will show if a file fragmented
fuser /etc/passwd lists the process numbers of local processes using the /etc/passwd file
fuser -cux /var shows which processes are using the given filesystem
fuser -cuxk /var it will kill the above processes
fuser -dV /tmp shows deleted files (inode) with process ids which were open by a process (so its space could not be freed up)
(-V: verbose will show the size of the files as well)
if we rm a file, while it is opened by a process its space will not free up.
solution: kill the process, wait for the process to finish or reboot the system
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HOW TO FIND FILES AFTER A SPECIFIC DATE:
touch mmddhhmm filename creates a file at a specific date
find /var -xdev -newer filename -ls
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CREATING FS with commands:
1. mkvg -y oravg -s 128 hdiskpower62 <--creates vg with 128MB pp
2. mklv -y oraloglv -t jfs2log -a e -r n oravg 1 hdiskpower62 <--creates loglv (-a: allocation (e:edge), -r: relocatable (n:no))
3. mklv -y oralv -t jfs2 -a e oravg 500 hdiskpower62 <--creates lv (-a: allocation (e:edge))
4. crfs -v jfs2 -a logname=oraloglv -d oralv -m /ora <--creates fs with specified loglv (set auto mount if needed)
5. mount /ora <--mount fs
6. chown -R oracle.dba /ora_backup <--set owner/permission
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EXTENDING FS with commands:
1. extendvg oravg hdiskpower63 <--extends vg with hdisk
2. chlv -x 1024 oralv <--set the maximum number of logical partitions if needed
3. extendlv oralv 20 hdiskpower63 <--extends lv to the specified hdisk
4. lslv -m oralv <--check allocations if needed
5. lsfs -q /ora <--shows new size of the lv (copy value of 'lv size')
6. chfs -a size=146800640 /ora <--use the 'lv size' value to enlarge fs
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HOW TO CORRECT CORRUPTED FS:
1. fsck /fs1 <--checks fs consistency (should not run on a mounted file system)
2. umount /fs1 <--umounts fs
If umount fails:
fuser -cux /fs1 <--shows processes running in the fs
fuser -kcux /fs1 <--kills the above processes (kill -9 works as well) (inittab/repawn processes will be there again)
umount /fs1
3. fsck -y /fs1 <--corrects errors
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CANNOT UNMOUNT FILE SYSTEMS:
-files are open or a user is using a directory in the fs:
fuser <--determines the PIDs for all processes that have open references within the fs
kill <--these processes can be killed
-loaded kernel extension:
genkex <--reports all loaded kernel extension
-file systems are still mounted within that file system:
umount <--umount first the embedded file systems!!!!!
-you can check processes using it with lsof:
lsof /home <--it will show the pids what should be terminated (kill <pid>)
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HOW TO COPY A FILESYSTEM TO A NEW VG:
command cplv is useful as it will copy at pp (lp) level not files (if there are many files cplv is better)
1. create vg if needed (loglv as well) <--we created bbvg, with log devce:bbloglv
2. umount /domo <--umount fs that you want to copy (/domo is the fs, domolv is its lv)
3. cplv -v bbvg domolv <--copy domolv to bbvg (it will create a new lv there like fslv01)
4. chfs -a dev=/dev/fslv01 -a log=/dev/bbloglv /domo <--changes the log device for fs to the one which we created in the new vg
(chfs -a dev=/dev/fslv01 -a log=INLINE /domo <--if we have inline log)
5. fsck -p /dev/fslv01 <--ensure fs integrity
6. mount /domo <--mount fs
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HOW TO COPY A FILESYSTEM (in the same vg):
1. create temporary fs
extendvg macavg hdiskX hdiskY <--add storage to vg
mkdir /maca_u10/macatmp <--create tmp mount point
chown oramaca.dbamaca /maca_u10/macatmp <--set rights
mklv -t jfs2 -y macatmplv macavg 1596 hdiskX hdiskY <--create temp lv (-y: new lv name, 1596: number of lps)
(if no jfslog, then mklv -t jfs2log..., and logform)
crfs -v jfs2 -d macatmplv -m /maca_u10/macatmp <--create temp fs (-d: device name, -m: mount point)
check if everything is identical <--df, lsfs, mount
2. copy data to temporary fs
umount /maca_u10/macaoradata
mount -r /maca_u10/macaoradata <--mount with read only
a.
cp -prh /maca_u10/oradata/* /maca_u10/macatmp/ <--this is good if small number of files need to be copied
or
b.
cd /maca_u10/macaoradata
tar cvf - . | (cd <tempnewfs> && tar xvf -) <--it copies everything from here to tempnewfs (file size limit? 6GB OK)
ls -lR | wc -l <--check if everything is identical, for both dir
3. rename lv and fs
umount /maca_u10/oradata
umount /maca_u10/macatmp
chlv -n macaoradatalv_o macaoradatalv <--rename oradatalv to old (chlv -n newlv oldlv)
chfs -m /maca_u10/oradata_o /maca_u10/oradata <--rename oradata fs to old fs (chfs -m newmnt oldmnt)
chlv -n macaoradatalv macatmplv <--rename tmplv to oradatalv
chfs -m /maca_u10/oradata /maca_u10/macatmp <--rename tmp fs to oradata fs
fsck /maca_u10/oradata <--fsck, before mount
mount /maca_u10/oradata
chown oramaca.dbamaca /maca_u10/oradata <--check (set) rights (if needed)
4. create mirror
rmfs /maca_u10/oradata_o <--remove old fs (if space needed)
rmdir /maca_u10/macatmp; rmdir /maca_u10/oradata_o <--remove dirs: macatmp, oradata_o
mklvcopy macaoradatalv 2 hdiskX hdiskY <--mirror oradatalv (2: 2 copies)
syncvg -l macaoradatalv <--synchronization
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BACKUP/RECREATE/RESTORE FILESYSTEM:
1. cd /filesystem
2. tar -cvf /tmp/filesystem.tar ./* <--it creates a backup of all the files in the fs
3. cd /
4. umount /filesystem
5. mkfs /filesystem
6. mount /filesystem
7. cd /filesystem
8. tar -xvf /tmp/filesystem.tar > /dev/null <--restores the data (output redirected, as displaying is time consuming)
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CHANGING THE LOG LOGICAL VOLUME:
If an fs is write extensive, the use of the log logical volume can cause io bottleneck if it is placed on the same disk.
(e.g. data-fs is located on hdisk2)
1. umount /data-fs <--umount the fs for which you want to create the new log logical volume
2. mlv -t jfs2log -y datafsloglv datavg 1 hdisk1 <--create a new log logical volume
3. logform /dev/datafsloglv <--format the log
4. chfs -a log=/dev/datafsloglv /data-fs <--it will modify /etc/filesystems to consist the new settings
5. getlvcb -ATdatalv <--just for checking if lvcb is updated
6. mount /data-fs <--mount back the changed filesystem
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REMOVING A FILE WITH SPECIAL CHARACTERS:
1. find inode number
root@bb_lpar: /tmp/bb # ls -i
49 <--the name of the file is empty
35 commands
47 lps.txt
2. remove file by inode number
root@bb_lpar: /tmp/bb # find . -inum 49 -exec rm '{}' \;
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FILESYSTEM CLEANUP HINTS:
find large files:
find . -xdev -size +4000000c -exec ls -l {} \; <--it will list files larger than 4MB in the fs
find . -type f | xargs ls -s | sort -rn | head <--10 largest file (if there is another fs under it, it will search there too)
find . -type f -size +10000 | while read X ; do du -sm "$X" ; done | sort -n | tail -n 15 <--15 largest file
/etc:
/etc/perf/daily/ <--xmdaily logs can be removed if not needed
(can be removed from inittab and xm processes can be killed)
who /etc/security/failedlogin <--lists failed logins
> /etc/security/failedlogin <--clears that file
/usr:
/usr/websm/pc_client <--windows, exe files can be removed
/var:
/var/adm/wtmp:
who /var/adm/wtmp <--shows the contents of that file
/usr/sbin/acct/fwtmp < /var/adm/wtmp | tail -5000 > /tmp/wtmp.asc <--converts wtmp to ascii, saves last 500 lines
/usr/sbin/acct/fwtmp -ic < /tmp/wtmp.asc > /var/adm/wtmp <--converts back to original format
rm /tmp/wtmp.asc <--delete the ascii file
/var/adm/cron/log:
> /var/adm/cron/log <--this can be cleared
/var/spool/lpd:
stopsrc -s qdaemon <--stops qdaemon
rm /var/spool/lpd/qdir/* <--clears dir
rm /var/spool/lpd/stat/*
rm /var/spool/qdaemon/*
startsrc -s qdaemon <--starts qdaemon
/var/spool/mail <--under this dir, not needed mails can be cleared as well
/var/adm/sulog <--this file can be reduced (cleared) as well
--------------------------
A file system is a hierarchical tree structure of files and directories. Some tasks are performed more efficiently on a file system than on each directory within the file system. For example, you can back up, move, or secure an entire file system.
File systems are associated with devices (logical volumes) represented by special files in /dev. When a file system is mounted, the logical volume and its contents are connected to a directory in the hierarchical tree structure. You can access both local and remote file systems using the mount command.
AIX supports these file system types:
JFS Journaled File System which exists within a Logical Volume on disk
JFS2 Enhanced Journaled File System which exists within a Logical Volume on disk
CDRFS CD-ROM File System on a Compact Disc
NFS Network File System accessed across a network
UDF Universal Disk Format (DVD ROM media)
GPFS General Parallel Filesystem
SMBFS Server Message Block Filesystem (cifs_fs, samba share)
All of the information about the file system is centralized in the /etc/filesystems file. Most of the file system maintenance commands take their defaults from this file. The file is organized into stanza names that are file system names and contents that are attribute-value pairs specifying characteristics of the file system.
/tmp: <-- names the directory where the file system is normally mounted
dev = /dev/hd3 <-- for local mounts identifies the block special file where the file system reside
for remote mounts, it identifies the file or directory to be mounted
vfs = jfs2 <-- specifies the type of mount. For example, vfs=nfs
log = /dev/hd8 <-- full path name of the filesystem logging logical volume (only for jfs and jfs2)
mount = automatic <-- used by the mount command to determine whether this file system should be mounted by default
type = nas <-- several file systems can be mounted by giving the value as an argument to the -t flag (mount -t nas)
check = false <-- used by the fsck command to determine the default file systems to be checked
vol = /tmp <-- used by the mkfs command when initiating the label on a new file system
free = false <-- it is there because of unix traditions only (It is totally ignored by any and all AIX commands)
(df command in traditional UNIX would use it to determine which file systems to report)
For the option mount, these are valid entries: automatic, true, false, removable, and readonly:
automatic fs is to be mounted at boot; this is usually used for system-defined file systems.
true mount all is allowed to mount this file system.
false mount will only occur when the file system is specified as an argument to the mount command, or the type is used for mount.
The asterisk (*) is the comment character used in the /etc/filesystems file.
To remove a file system data from /etc/filesystems: imfs -x -l <lvname>
System-Created File Systems in AIX
The six standard file systems in AIX Versions 5 and higher are /, /home, /usr, /proc, /tmp, and /var. Each of these file systems is always associated with a logical volume name:
Logical Volume File System or Description
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hd1 /home (users' home dir)
hd2 /usr (operating system commands, libraries and application programs)
hd3 /tmp (temporary space for all users)
hd4 / (critical files for system operations, programs that complete the boot process)
hd5 <boot logical volume>
hd6 <primary paging space>
hd8 <primary JFS or JFS2 log>
hd9var /var (variable spool and log files)
hd10opt /opt (freeware programs)
/proc /proc (pseudo fs kept in memory to support threads)
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Superblock
In a JFS, the superblock is the first addressable block (and a backup at the thirty-first addressable block) on a file system. It is 4096 bytes in size. The superblock is very important because a file system cannot be mounted if the superblock is corrupted. This is why there is a secondary or backup superblock at block 31. The superblock contains the following: size of the filesystem, number of datablocks in the fs, state of the fs...
# dd count=1 bs=4k skip=31 seek=1 if=/dev/hd4 of=/dev/hd4 <--this will restore the superblock from block #31
# fsck -p <fs> <--this will copy also the superblock from #31
# dumpfs /usr <--shows the superblock, i-node map, and disk map information
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i-node (index node)
A file system has a fixed number of i-nodes that are located following the superblock. i-nodes contain information about files, including the location of the data on the disk. They contain all of the identifying information about files (file type, size, permissions, user/group/owner, create/modification and last access dates) except for the file name, which is stored in the directory, and the contents of the file, which are stored in the data blocks. Each file or directory has an i-node associated with it. AIX reserves a number of i-nodes for files and directories every time a file system is created, and if all the available inodes are used, no more files can be created, even if the fs has free space.
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jfslog
AIX uses a journaled file system, meaning that certain i-node information is stored in a transaction log during writes. Its real value is in maintaining the integrity of the file system. Journaled file systems enable faster system reboots after system crashes. Each volume group has a jfslog file that is automatically created when the first file system is created in that volume group. The jfslog ensures the integrity of a file system by immediately writing all meta-data information to itself. Meta-data is information about the file system, such as changes to the i-nodes and the free lists. The jfslog keeps track of what is supposed to happen to the file system and whether it gets done. You are allowed to have a separate log for each filesystem.
(If a jfslog has been created manually, the logform command should be used to activate it as the jfslog for that vg.)
------------------------
Special or device files
A special file, sometimes called device file is associated with a particular hw device or other resource of the computer system. AIX uses them to provide file I/O access to character and block device drivers. Special files are distinguished from other files by having a "c" or "b" stored in the i-nodes, and they are located under the /dev directory. Character and block I/O requests are performed by issuing a read or write request on the device file:
- Character device file: Character devices (tape drives, tty devices) are capable of doing sequential I/O.
- Block device file: Block devices can only do random I/O, such as disk devices.
mknod: creates new special files (i-node and the file type (c or b) sould be set), major minor numbers will be written into the i-node
------------------------
Directories
The directory entry contains an index number associated with the file's i-node, the file name....
Every well formed directory contains the entries: . and ..
-.: points to the i-node for the directory itself
-..: points to the i-node for the parent directory
Because directory entries contain file names paired with i-nodes, every directory entry is a link.
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Links
Links are connection between a file name and an i-node. The i-node number actually identifies the file not the filename. By using links, any i-node or file can be known by many different names.
-hard link: Hard links can be created only between files that are in the same fs.
(when the last hard link is removed , the i-node and its data are deleted)
# ls -li: (bello is a hard link, and link count 2 shows it)
4 -rw-r--r-- 2 root system 0 Jul 8 23:27 bello
-symbolic link: Allow access to data in other filesystems from a new filename.
# ls -li: (bello is a sym. link, and the first character "l" shows this)
lrwxrwxrwx 1 root system 15 Jul 8 23:30 bello -> /test_fs1/hello
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NameFS (Name File System)
A NameFS is a pseudo-file system that lets you access a directory through two different path names. With a NameFS you can create a second path and you don't have to change permissions, copy, move, rename or even touch the original file system.
You could use a Name File System to set up a directory with:
-an alternate path (so it’s like a shortcut)
-different permissions (e.g. when some applications or users should have read-only access)
-other mount attributes such as Direct I/O (dio) or Concurrent I/O (cio)
How to setup NameFS:
1. mkdir -p /shortcut <--create a dir, which will be the mount point for the new Name file System
2.:
mount -v namefs /some/long/path /shortcut <--with this you got access to the files via 2 paths
mount -v namefs -o ro /data/report /data_reports <--with this you can make a read only mount of a dir
mount -v namefs -o cio /db2/W01/redo /deb2redo <--with this you can mount a dir with CIO to improve I/O
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crfs ... creates a file system (crfs creates lv as well; mkfs will create an fs over an already created lv)
crfs -v jfs2 -d W01origlogAlv -m /oracle/W01/origlogA -A yes -p rw -a options=cio -a agblksize=512
mount displays information about all the currently mounted file systems
mount dir_name mount the file system according to the entry in /etc/filesystems
mount lv_name dir_name mount the file system to another lv than in /etc/filesystems
umount dir_name umount the filesystem
mount -a or mount -all mounts all the file systems at one time
lsfs displays the characteristics of file systems
lsfs -q more detailed info about the fs (lv size...) (it queries the superblock)
(-v: list filesytems belonging to given fs type (jfs2, nfs); -u: lists filesystems in the given mount group)
rmfs /test removes a file system
rmfs -r /test removes the mount point also
chfs -a size=+5G /shadowtemp it will increase by 5G the fs (-5G can be used as well, or 5G will set tthe size of the fs to 5GB)
(if fs was reduced but space is not freed up defragfs could help)
chfs -a options='rw' /shadow shows with lsfs rw (I think rw is the deafault anyway)
imfs -x -l <lvname> remove a file system data from /etc/filesystems
fsck checks file system consistency (should not run on a mounted file system)
defragfs /home improves or reports the status of contiguous space within a file system
ls -ldi <dir> shows inode number in the first column
istat /etc/passwd display information regarding a particular inode (last updated, modified, accessed)
(update: change in the inode (file name, owner...); modified: change in the content of the file or dir)
df monitor file system growth
du dir_name (disk usage), to find which files are taking up the most space
du -sm * | sort -rn | head shows every dir size in MB (du -sk * the same in KB), the first 10 largest
skulker cleans up file systems by removing unwanted or obsolete files
fileplace <filename> displays the placement of file blocks within logical or physical volumes, it will show if a file fragmented
fuser /etc/passwd lists the process numbers of local processes using the /etc/passwd file
fuser -cux /var shows which processes are using the given filesystem
fuser -cuxk /var it will kill the above processes
fuser -dV /tmp shows deleted files (inode) with process ids which were open by a process (so its space could not be freed up)
(-V: verbose will show the size of the files as well)
if we rm a file, while it is opened by a process its space will not free up.
solution: kill the process, wait for the process to finish or reboot the system
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HOW TO FIND FILES AFTER A SPECIFIC DATE:
touch mmddhhmm filename creates a file at a specific date
find /var -xdev -newer filename -ls
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CREATING FS with commands:
1. mkvg -y oravg -s 128 hdiskpower62 <--creates vg with 128MB pp
2. mklv -y oraloglv -t jfs2log -a e -r n oravg 1 hdiskpower62 <--creates loglv (-a: allocation (e:edge), -r: relocatable (n:no))
3. mklv -y oralv -t jfs2 -a e oravg 500 hdiskpower62 <--creates lv (-a: allocation (e:edge))
4. crfs -v jfs2 -a logname=oraloglv -d oralv -m /ora <--creates fs with specified loglv (set auto mount if needed)
5. mount /ora <--mount fs
6. chown -R oracle.dba /ora_backup <--set owner/permission
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EXTENDING FS with commands:
1. extendvg oravg hdiskpower63 <--extends vg with hdisk
2. chlv -x 1024 oralv <--set the maximum number of logical partitions if needed
3. extendlv oralv 20 hdiskpower63 <--extends lv to the specified hdisk
4. lslv -m oralv <--check allocations if needed
5. lsfs -q /ora <--shows new size of the lv (copy value of 'lv size')
6. chfs -a size=146800640 /ora <--use the 'lv size' value to enlarge fs
--------------------------------------------
HOW TO CORRECT CORRUPTED FS:
1. fsck /fs1 <--checks fs consistency (should not run on a mounted file system)
2. umount /fs1 <--umounts fs
If umount fails:
fuser -cux /fs1 <--shows processes running in the fs
fuser -kcux /fs1 <--kills the above processes (kill -9 works as well) (inittab/repawn processes will be there again)
umount /fs1
3. fsck -y /fs1 <--corrects errors
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CANNOT UNMOUNT FILE SYSTEMS:
-files are open or a user is using a directory in the fs:
fuser <--determines the PIDs for all processes that have open references within the fs
kill <--these processes can be killed
-loaded kernel extension:
genkex <--reports all loaded kernel extension
-file systems are still mounted within that file system:
umount <--umount first the embedded file systems!!!!!
-you can check processes using it with lsof:
lsof /home <--it will show the pids what should be terminated (kill <pid>)
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HOW TO COPY A FILESYSTEM TO A NEW VG:
command cplv is useful as it will copy at pp (lp) level not files (if there are many files cplv is better)
1. create vg if needed (loglv as well) <--we created bbvg, with log devce:bbloglv
2. umount /domo <--umount fs that you want to copy (/domo is the fs, domolv is its lv)
3. cplv -v bbvg domolv <--copy domolv to bbvg (it will create a new lv there like fslv01)
4. chfs -a dev=/dev/fslv01 -a log=/dev/bbloglv /domo <--changes the log device for fs to the one which we created in the new vg
(chfs -a dev=/dev/fslv01 -a log=INLINE /domo <--if we have inline log)
5. fsck -p /dev/fslv01 <--ensure fs integrity
6. mount /domo <--mount fs
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HOW TO COPY A FILESYSTEM (in the same vg):
1. create temporary fs
extendvg macavg hdiskX hdiskY <--add storage to vg
mkdir /maca_u10/macatmp <--create tmp mount point
chown oramaca.dbamaca /maca_u10/macatmp <--set rights
mklv -t jfs2 -y macatmplv macavg 1596 hdiskX hdiskY <--create temp lv (-y: new lv name, 1596: number of lps)
(if no jfslog, then mklv -t jfs2log..., and logform)
crfs -v jfs2 -d macatmplv -m /maca_u10/macatmp <--create temp fs (-d: device name, -m: mount point)
check if everything is identical <--df, lsfs, mount
2. copy data to temporary fs
umount /maca_u10/macaoradata
mount -r /maca_u10/macaoradata <--mount with read only
a.
cp -prh /maca_u10/oradata/* /maca_u10/macatmp/ <--this is good if small number of files need to be copied
or
b.
cd /maca_u10/macaoradata
tar cvf - . | (cd <tempnewfs> && tar xvf -) <--it copies everything from here to tempnewfs (file size limit? 6GB OK)
ls -lR | wc -l <--check if everything is identical, for both dir
3. rename lv and fs
umount /maca_u10/oradata
umount /maca_u10/macatmp
chlv -n macaoradatalv_o macaoradatalv <--rename oradatalv to old (chlv -n newlv oldlv)
chfs -m /maca_u10/oradata_o /maca_u10/oradata <--rename oradata fs to old fs (chfs -m newmnt oldmnt)
chlv -n macaoradatalv macatmplv <--rename tmplv to oradatalv
chfs -m /maca_u10/oradata /maca_u10/macatmp <--rename tmp fs to oradata fs
fsck /maca_u10/oradata <--fsck, before mount
mount /maca_u10/oradata
chown oramaca.dbamaca /maca_u10/oradata <--check (set) rights (if needed)
4. create mirror
rmfs /maca_u10/oradata_o <--remove old fs (if space needed)
rmdir /maca_u10/macatmp; rmdir /maca_u10/oradata_o <--remove dirs: macatmp, oradata_o
mklvcopy macaoradatalv 2 hdiskX hdiskY <--mirror oradatalv (2: 2 copies)
syncvg -l macaoradatalv <--synchronization
--------------------------------------------
BACKUP/RECREATE/RESTORE FILESYSTEM:
1. cd /filesystem
2. tar -cvf /tmp/filesystem.tar ./* <--it creates a backup of all the files in the fs
3. cd /
4. umount /filesystem
5. mkfs /filesystem
6. mount /filesystem
7. cd /filesystem
8. tar -xvf /tmp/filesystem.tar > /dev/null <--restores the data (output redirected, as displaying is time consuming)
--------------------------------------------
CHANGING THE LOG LOGICAL VOLUME:
If an fs is write extensive, the use of the log logical volume can cause io bottleneck if it is placed on the same disk.
(e.g. data-fs is located on hdisk2)
1. umount /data-fs <--umount the fs for which you want to create the new log logical volume
2. mlv -t jfs2log -y datafsloglv datavg 1 hdisk1 <--create a new log logical volume
3. logform /dev/datafsloglv <--format the log
4. chfs -a log=/dev/datafsloglv /data-fs <--it will modify /etc/filesystems to consist the new settings
5. getlvcb -ATdatalv <--just for checking if lvcb is updated
6. mount /data-fs <--mount back the changed filesystem
--------------------------------------------
REMOVING A FILE WITH SPECIAL CHARACTERS:
1. find inode number
root@bb_lpar: /tmp/bb # ls -i
49 <--the name of the file is empty
35 commands
47 lps.txt
2. remove file by inode number
root@bb_lpar: /tmp/bb # find . -inum 49 -exec rm '{}' \;
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FILESYSTEM CLEANUP HINTS:
find large files:
find . -xdev -size +4000000c -exec ls -l {} \; <--it will list files larger than 4MB in the fs
find . -type f | xargs ls -s | sort -rn | head <--10 largest file (if there is another fs under it, it will search there too)
find . -type f -size +10000 | while read X ; do du -sm "$X" ; done | sort -n | tail -n 15 <--15 largest file
/etc:
/etc/perf/daily/ <--xmdaily logs can be removed if not needed
(can be removed from inittab and xm processes can be killed)
who /etc/security/failedlogin <--lists failed logins
> /etc/security/failedlogin <--clears that file
/usr:
/usr/websm/pc_client <--windows, exe files can be removed
/var:
/var/adm/wtmp:
who /var/adm/wtmp <--shows the contents of that file
/usr/sbin/acct/fwtmp < /var/adm/wtmp | tail -5000 > /tmp/wtmp.asc <--converts wtmp to ascii, saves last 500 lines
/usr/sbin/acct/fwtmp -ic < /tmp/wtmp.asc > /var/adm/wtmp <--converts back to original format
rm /tmp/wtmp.asc <--delete the ascii file
/var/adm/cron/log:
> /var/adm/cron/log <--this can be cleared
/var/spool/lpd:
stopsrc -s qdaemon <--stops qdaemon
rm /var/spool/lpd/qdir/* <--clears dir
rm /var/spool/lpd/stat/*
rm /var/spool/qdaemon/*
startsrc -s qdaemon <--starts qdaemon
/var/spool/mail <--under this dir, not needed mails can be cleared as well
/var/adm/sulog <--this file can be reduced (cleared) as well
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