Difference between revisions of "Disks and filesystems"
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;dd if=/dev/zero of=./test.tmp bs=1G count=1 oflag=dsync;rm -f ./test.tmp | ;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 | ;dd if=/dev/zero of=./test.tmp bs=512 count=1000 oflag=dsync;rm -f ./test.tmp | ||
:Latency test | :Latency test | ||
| Line 34: | Line 34: | ||
On an empty disk you can do: | On an empty disk you can do: | ||
;dd if=/dev/zero of=/dev/sdb bs=8k count=10k | ;dd if=/dev/zero of=/dev/sdb bs=8k count=10k | ||
| − | :Test disk write speed if no | + | :Test disk write speed if no filesystem exists |
==Misc== | ==Misc== | ||
Revision as of 09:00, 18 August 2020
- badblocks -v- s /dev/sdb >badblocks.log
- Check a device for bad blocks
- fdisk /dev/sdb
- Manage disk partitions
- df -h
- Show filesystem block usage in human friendly format
- df -i
- Show filesystem inode usage
- ls -i <file>
- Show inode of <file>
- rm -i <file>
- Remove a file by its inode
- mount -t <fstype> -o <options> <devicefile> <mountpoint>
- Mount a filesystem (fstype and options can be omitted often)
- mount -o loop /path/to/my-iso-image.iso /mnt/iso
- Mount an .iso file
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