http://192.168.180.206:8001/ 2026-05-14T06:32:13+00:00 http://192.168.180.206:8001/ http://192.168.180.206:8001/_media/wiki:dokuwiki.svg text/html 2017-02-07T14:53:44+00:00 Anonymous (anonymous@undisclosed.example.com) http://192.168.180.206:8001/linux:fs:benchmark?rev=1486479224&do=diff apt-get install iozone3 iozone -R -l 5 -u 5 -r 4k -s 100m -F /f1 /f2 /f3 /f4 /f5 | tee -a /tmp/iozone_results.txt Automatic mode iozone -a -a option stands for automatic mode. This creates temporary test files from sizes 64k to 512MB for performance testing. This mode also uses 4k to 16M of record sizes for read and write (more on this later) testing. -a option will also execute all the 13 types of tests. text/html 2017-01-18T20:41:16+00:00 Anonymous (anonymous@undisclosed.example.com) http://192.168.180.206:8001/linux:fs:btrfs_as_root?rev=1484772076&do=diff BTRFS as root filesystem System overview * /dev/sda1 4.08GB ext4 “/” used 1.56GB, free 2.53GB * /dev/sda2 10.91GB extended * /dev/sda5 524MB swap * /dev/sda6 10.40GB ext4 “/home” 321MB used, 10.09GB free Boot from live-cd Btrfs support is heavily developed in Linux Kernel. So do not use old kernel. text/html 2025-03-24T07:32:31+00:00 Anonymous (anonymous@undisclosed.example.com) http://192.168.180.206:8001/linux:fs:btrfs_as_root2?rev=1742801551&do=diff BTRFS as root (LVM and raid) To setup BTRFS on 2 disc, first setup complete system for one disc, then connect 2nd disc and: * clone partition layout to 2nd disc * add 2nd disc to btrfs * rebalance btrfs * install grub on 2nd disc * configure system to start with degraded disc, include btrfs tools in initramfs text/html 2016-04-20T07:10:54+00:00 Anonymous (anonymous@undisclosed.example.com) http://192.168.180.206:8001/linux:fs:btrfs_vs_ext4?rev=1461136254&do=diff BTRFS vs EXT4 Setup New factory fresh disc 1TB WD Black WDC WD1003FZEX-00MK2A0. sudo hdparm -tT /dev/sdc /dev/sdc: Timing cached reads: 35212 MB in 2.00 seconds = 17633.75 MB/sec Timing buffered disk reads: 556 MB in 3.06 seconds = 181.66 MB/sec text/html 2016-04-21T11:49:11+00:00 Anonymous (anonymous@undisclosed.example.com) http://192.168.180.206:8001/linux:fs:btrfs_vs_zfs?rev=1461239351&do=diff BTRFS vs ZFS My target is to: * protect private files (Photos, documents) (of course I have scheduled backups to external device). On ZFS I can create subvolume with copies=2. On BTRFS with single disc it is not possible. * reduce e-mail disc space usage (compression, deduplication). On both I can enable compression with similar results. Deduplication works better on BTRFS, because I can specify small block size 4kB. Also is performed by external tool and it is not consuming RAM all the t… text/html 2021-05-02T09:34:38+00:00 Anonymous (anonymous@undisclosed.example.com) http://192.168.180.206:8001/linux:fs:btrfs?rev=1619948078&do=diff BTRFS References <https://www.howtoforge.com/a-beginners-guide-to-btrfs> <https://www.howtoforge.com/how-to-convert-an-ext3-ext4-root-file-system-to-btrfs-on-ubuntu-12.10> <http://www.oracle.com/technetwork/articles/servers-storage-admin/advanced-btrfs-1734952.html> Compression Create BTRFS filesystem on multiple block devices: mkfs.btrfs /dev/loop0 /dev/loop1 btrfs filesystem show /dev/loop0 Label: none uuid: e9a456cd-57d7-4355-a20a-77243d66722e Total devices 2 FS byte… text/html 2025-03-24T07:27:13+00:00 Anonymous (anonymous@undisclosed.example.com) http://192.168.180.206:8001/linux:fs:encrypted_swap?rev=1742801233&do=diff encrypted SWAP apt install cryptsetup auto create Auto create encrypted swap with random key for every boot. Problem is that given block device will be filled with random data when swap is created. So label / UUID is lost for next reboot. Need to use direct device names or use symlinks like text/html 2024-11-15T09:57:04+00:00 Anonymous (anonymous@undisclosed.example.com) http://192.168.180.206:8001/linux:fs:ext4?rev=1731664624&do=diff EXT4 Fragmentation viewers * <https://github.com/i-rinat/fragview> * <http://davtools.sourceforge.net/#screenshot> deduplication Not supported. Duplicated files can be removed and hardlinkied using 3rd party software: * rdfind is a program to find duplicate files and optionally list, delete them or replace them with symlinks or hard links; text/html 2020-10-07T06:30:42+00:00 Anonymous (anonymous@undisclosed.example.com) http://192.168.180.206:8001/linux:fs:file_level_enc?rev=1602052242&do=diff File level encryption FUSE based * cryfs - encrypt your files and store them in the cloud <https://www.cryfs.org>. * encfs - EncFS integrates file system encryption into the Unix(TM) file system. Encrypted data is stored within the native file system, thus no fixed-size loopback image is required. EncFS uses the FUSE kernel driver and library as a backend. text/html 2026-02-03T09:18:53+00:00 Anonymous (anonymous@undisclosed.example.com) http://192.168.180.206:8001/linux:fs:gpt?rev=1770110333&do=diff GPT convert MBR to GPT Note: this only converts. Booting will be broken. gdisk /dev/sda w Partition type UUIDs Partition_type_GUIDs * OS independent * Unused entry 00000000-0000-0000-0000-000000000000 * EFI System partition C12A7328-F81F-11D2-BA4B-00A0C93EC93B text/html 2021-02-17T07:51:46+00:00 Anonymous (anonymous@undisclosed.example.com) http://192.168.180.206:8001/linux:fs:luks?rev=1613548306&do=diff https://wiki.archlinux.org/index.php/Dm-crypt/Encrypting_an_entire_system|dm-crypt/Encrypting an entire system LUKS on LVM vs LVM on LUKS LUKS on LVM Benefit: * Every logical volume is encrypted with separate password * good for multiuser environment * root system can be on unencrypted partition (no password to boot). The same can be achieved with LVM on LUKS on separate partition. text/html 2024-03-22T09:10:31+00:00 Anonymous (anonymous@undisclosed.example.com) http://192.168.180.206:8001/linux:fs:overlayfs?rev=1711098631&do=diff overlayfs restore changes From overlayfs.txt: Changes to the underlying filesystems while part of a mounted overlay filesystem are not allowed. If the underlying filesystem is changed, the behavior of the overlay is undefined, though it will not result in a crash or deadlock. text/html 2025-03-24T08:49:14+00:00 Anonymous (anonymous@undisclosed.example.com) http://192.168.180.206:8001/linux:fs:sgdisk?rev=1742806154&do=diff sgdisk # print sgdisk -p $DISK # backup partitions to file sgdisk -b sgdisk-backup.bin # replicate partition layout sgdisk /dev/sda -R $DISK # randomize GUIDs sgdisk -G $DISK # Clear the partition table: sgdisk --zap-all $DISK # Create EFI system partition (for use now or in the future): sgdisk -n1:1M:+1G -t1:EF00 $DISK # Create BIOS boot partition, skip if you don't use this: sgdisk -a1 -n5:24K:+1000K -t5:EF02 $DISK # Create main partition: sgdisk -n2:0:0 $DISK text/html 2022-02-15T06:42:43+00:00 Anonymous (anonymous@undisclosed.example.com) http://192.168.180.206:8001/linux:fs:ssd_cache?rev=1644907363&do=diff HDD on SSD caching Speed up HDDs with additional SSD/NVMe caching. Options: * OpenZFS * it is possible to add cache and log devices to ZFS pool. Log is a journal for synchronous writes. * LVM DM-Cache * No HDD reformating if it is already using LVM text/html 2020-09-17T17:49:19+00:00 Anonymous (anonymous@undisclosed.example.com) http://192.168.180.206:8001/linux:fs:ubi?rev=1600364959&do=diff UBI and UBIFS Simulate MTD device rmmod mtdram # total_size:Total device size in KiB (ulong) # erase_size: Device erase block size in KiB (ulong) modprobe mtdram total_size=239616 erase_size=16 UBI How to mount UBI image. cat /proc/mtd flash_erase /dev/mtd1 0 0 ubiformat /dev/mtd1 -f image.ubi ubiattach -p /dev/mtd1 mount -t ubifs /dev/ubi0_0 /mnt/ubifs text/html 2025-07-17T14:40:34+00:00 Anonymous (anonymous@undisclosed.example.com) http://192.168.180.206:8001/linux:fs:xfs?rev=1752763234&do=diff XFS mkfs.xfs options: * -K Do not attempt to discard blocks at mkfs time. * -d su=64k,sw=4 stripe unit 64k stripe width (number of discs) 4 Create XFS on zvol: mkfs.xfs -K /dev/... <https://web.archive.org/web/20240113230117/https://xfs.org/index.php/XFS_FAQ#Q:_How_to_calculate_the_correct_sunit,swidth_values_for_optimal_performance> <https://doc.beegfs.io/latest/advanced_topics/storage_tuning.html#mount-options> noatime,nodiratime,logbufs=8,logbsize=256k,largeio,inode64,swalloc,… text/html 2021-05-10T18:42:13+00:00 Anonymous (anonymous@undisclosed.example.com) http://192.168.180.206:8001/linux:fs:zfs?rev=1620672133&do=diff ZFS ZFS 101—Understanding ZFS storage and performance <https://lists.debian.org/debian-user/2012/05/msg01026.html> Features: * data pools (tanks) are abstraction aggregate block devices (simple, mirror, raidz, spares, etc) * data set is created on data pool or another (parent) data set. * whole data pool space is shared between dataset (no fixed partition size problem). Size of data set (and its descendants) can be limited using quota