Disks and filesystems: Difference between revisions
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:Mount a filesystem (fstype and options can be omitted often) | :Mount a filesystem (fstype and options can be omitted often) | ||
;mount -a | |||
:Mount all filesystems in [[#fstab|/etc/fstab]] with the <code>auto</code> option. | |||
;mount -o loop /path/to/my-iso-image.iso /mnt/iso | ;mount -o loop /path/to/my-iso-image.iso /mnt/iso | ||
:Mount an .iso file | :Mount an .iso file | ||
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Defaults (specified by defaults) are for ext3 filesystems: rw,suid,dev,exec,auto,nouser,async (read/write, set userID, dev?, allow execution of executables, mount during boot and when <code>mount -a</code> is done, only root can mount this, do not wait for the host to have written to storage) | Defaults (specified by defaults) are for ext3 filesystems: rw,suid,dev,exec,auto,nouser,async (read/write, set userID, dev?, allow execution of executables, mount during boot and when <code>mount -a</code> is done, only root can mount this, do not wait for the host to have written to storage) | ||
See the [https://en.wikipedia.org/wiki/Fstab fstab wikipedia page]. | See the [https://en.wikipedia.org/wiki/Fstab fstab wikipedia page] for more. | ||
==Performance== | ==Performance== | ||
Revision as of 09:13, 31 January 2025
- badblocks -v- s /dev/sdb >badblocks.log
- Check a device for bad blocks
- fdisk /dev/sdb # Deprecated
- gdisk /dev/sdb
- Manage disk (GPT) partitions
- df -h
- Show filesystem block usage in human friendly format
- df -i
- Show filesystem inode usage
- df -P
- Report file-system information in parseble format.
- du -shx *
- Report disk usage for all files and directories in the current directory. Do not count files on other filesystems (-x) and do not follow symbolic links (default)
- ls -i <file>
- Show inode of <file>
- mount -t <fstype> -o <options> <devicefile> <mountpoint>
- Mount a filesystem (fstype and options can be omitted often)
- mount -a
- Mount all filesystems in /etc/fstab with the
autooption. - mount -o loop /path/to/my-iso-image.iso /mnt/iso
- Mount an .iso file
fstab
Configuration file to store mounts. Example for NFS mounts:
<host>:<path> <mountpoint> nfs defaults 0 0- Enable mount by;
mount <mountpoint> - Mount the <path> exported by <host> on directory <mountpoint> using the NFS protocol with default setting (see below), do not automatically backup when dump is executed and do not fsck when mounted at boot time.
<host>:<path> <mountpoint> nfs defaults,noauto 0 0- Same as above but do not mount at boot-time
Defaults (specified by defaults) are for ext3 filesystems: rw,suid,dev,exec,auto,nouser,async (read/write, set userID, dev?, allow execution of executables, mount during boot and when mount -a is done, only root can mount this, do not wait for the host to have written to storage)
See the fstab wikipedia page for more.
Performance
The graphical utility Disks has a benchmark option.
- dd if=/dev/zero of=./test.tmp bs=1G count=1 oflag=dsync;rm -f ./test.tmp
- Check plain write speed
- dd if=/dev/zero of=./test.tmp bs=512 count=1000 oflag=dsync;rm -f ./test.tmp
- Latency test
On an empty disk you can do:
- dd if=/dev/zero of=/dev/sdb bs=8k count=10k
- Test disk write speed if no filesystem exists
Misc
- /dev/null
- The unix black hole. Write always succeeds with no effect at all.
- /dev/zero
- Provides an unlimited amount of null characters (ASCII 0). Can be used for cleaning disks or benchmarking (see #Performance)
- Writing to /dev/zero is the same as writing to /dev/null