161 commands · 7 cheat sheets · Linux

Storage and Filesystems master quick reference

Browse 161 commands from 7 focused cheat sheets on page 1 of 1. Each example opens its matching detailed section.

Storage and Filesystems · 20 commands

ext4, XFS, and Filesystem Repair Cheat Sheet

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UseSyntaxExamples
Resolve a mount sourcefindmnt --target /srv/data -o \ TARGET,SOURCE,FSTYPE,OPTIONS,MAJ:MINView examples
Show block topologylsblk --fs --output \ NAME,KNAME,TYPE,FSTYPE,FSVER,LABEL,UUID,MOUNTPOINTSView examples
Probe filesystem metadatasudo blkid /dev/mapper/vg_data-lv_projectsView examples
Read device healthsudo smartctl --all /dev/nvme0n1View examples
Find storage errorsjournalctl -k -g \ 'I/O error|EXT4-fs error|XFS.*Corruption|nvme|ata' \ --since today --no-pagerView examples
Inspect ext metadatasudo dumpe2fs -h /dev/mapper/vg_data-lv_projectsView examples
Read-only ext checksudo e2fsck -f -n /dev/mapper/vg_data-lv_projectsView examples
Preen ext filesystemsudo e2fsck -f -p /dev/mapper/vg_data-lv_projectsView examples
List backup superblockssudo mke2fs -n /dev/mapper/vg_data-lv_projectsView examples
Show ext parameterssudo tune2fs -l /dev/mapper/vg_data-lv_projectsView examples
Show XFS geometrysudo xfs_info /srv/dataView examples
Create XFS metadata imagesudo xfs_metadump /dev/mapper/vg_data-lv_projects \ /recovery/projects.metadumpView examples
Check XFS without changessudo xfs_repair -n /dev/mapper/vg_data-lv_projectsView examples
Repair XFSsudo xfs_repair /dev/mapper/vg_data-lv_projectsView examples
Zero a corrupt XFS logsudo xfs_repair -L /dev/mapper/vg_data-lv_projectsView examples
Mount read-onlysudo mount -o ro /dev/mapper/vg_data-lv_projects \ /mnt/recoveryView examples
Mount ext without journal replaysudo mount -t ext4 -o ro,noload \ /dev/mapper/vg_data-lv_projects /mnt/recoveryView examples
Mount XFS without recoverysudo mount -t xfs -o ro,norecovery \ /dev/mapper/vg_data-lv_projects /mnt/recoveryView examples
Unmount normallysudo umount /srv/dataView examples
Find mount userssudo fuser -vm /srv/dataView examples

Storage and Filesystems · 30 commands

Linux Software RAID with mdadm Cheat Sheet

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List active MD arrayscat /proc/mdstatView examples
Inspect array geometrysudo mdadm --detail /dev/md/dataView examples
Inventory stable identitieslsblk -o \ NAME,PATH,SIZE,MODEL,SERIAL,TYPE,FSTYPE,MOUNTPOINTSView examples
Examine one MD superblocksudo mdadm --examine /dev/disk/by-id/ATA_MEMBER_A-part1View examples
Group discovered metadatasudo mdadm --examine --scanView examples
Create a named RAID1sudo mdadm --create /dev/md/data -l1 -n2 -e1.2 -N data \ -b internal /dev/disk/by-id/A-part1 \ /dev/disk/by-id/B-part1View examples
Create near-layout RAID10sudo mdadm --create /dev/md/data -l10 -p n2 -n4 \ /dev/disk/by-id/A-part1 /dev/disk/by-id/B-part1 \ /dev/disk/by-id/C-part1 /dev/disk/by-id/D-part1View examples
Assemble configured arrayssudo mdadm --assemble --scanView examples
Assemble explicit members read-onlysudo mdadm --assemble --readonly /dev/md/data \ /dev/disk/by-id/A-part1 /dev/disk/by-id/B-part1View examples
Stop an unused arraysudo mdadm --stop /dev/md/dataView examples
Mark a member faultysudo mdadm /dev/md/data --fail \ /dev/disk/by-id/ATA_FAILED-part1View examples
Detach a failed membersudo mdadm /dev/md/data --remove \ /dev/disk/by-id/ATA_FAILED-part1View examples
Add a replacement membersudo mdadm /dev/md/data --add \ /dev/disk/by-id/ATA_REPLACEMENT-part1View examples
Replace while the old disk readssudo mdadm /dev/md/data --replace \ /dev/disk/by-id/OLD-part1 --with \ /dev/disk/by-id/SPARE-part1View examples
Watch rebuild progresswatch -n 5 cat /proc/mdstatView examples
Read current sync actioncat /sys/block/md0/md/sync_actionView examples
Read precise sync progresscat /sys/block/md0/md/sync_completedView examples
Inspect per-array speed limitscat /sys/block/md0/md/sync_speed_min \ /sys/block/md0/md/sync_speed_maxView examples
Run one monitoring passsudo mdadm --monitor --scan --oneshotView examples
Add an internal bitmapsudo mdadm --grow /dev/md/data --bitmap=internalView examples
Remove a write-intent bitmapsudo mdadm --grow /dev/md/data --bitmap=noneView examples
Start a consistency checkecho check | sudo tee /sys/block/md0/md/sync_actionView examples
Read mismatch countcat /sys/block/md0/md/mismatch_cntView examples
Request consistency repairecho repair | sudo tee /sys/block/md0/md/sync_actionView examples
Grow a parity arraysudo mdadm --grow /dev/md/data -n4 \ --backup-file=/mnt/rescue/md-data.reshapeView examples
Reassemble with reshape backupsudo mdadm --assemble --scan \ --backup-file=/mnt/rescue/md-data.reshapeView examples
Print array configurationsudo mdadm --detail --scanView examples
Update Debian-family initramfssudo update-initramfs -uView examples
Update dracut initramfssudo dracut --forceView examples
Read physical-disk SMART datasudo smartctl -x /dev/disk/by-id/ATA_MEMBER_AView examples

Storage and Filesystems · 16 commands

Linux Storage and Filesystems Cheat Sheet

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UseSyntaxExamples
Show block-device topologylsblk -o \ NAME,TYPE,SIZE,FSTYPE,FSVER,LABEL,UUID,MOUNTPOINTSView examples
Show filesystem overviewlsblk --fsView examples
Probe a specific devicesudo blkid /dev/sdb1View examples
List mounted filesystemsfindmnt --real --output TARGET,SOURCE,FSTYPE,OPTIONSView examples
Resolve a path's mountfindmnt --target /var/lib/appView examples
Test a mount pointmountpoint --quiet /mnt/archiveView examples
Show filesystem capacitydf -hT /var/lib/appView examples
Show inode capacitydf -ih /var/lib/appView examples
Measure one treedu -sh -- /var/lib/appView examples
Compare top-level childrendu -xhd1 -- /var/lib/app | sort -hView examples
Verify fstabsudo findmnt --verify --verboseView examples
Mount read-onlysudo mount --read-only --source /dev/sdb1 --target \ /mnt/reviewView examples
Unmount by targetsudo umount -- /mnt/reviewView examples
Synchronize one filesync --data /var/lib/app/database.dbView examples
Find mount userssudo fuser --mount --verbose /mnt/reviewView examples
Inspect open pathssudo lsof +D /mnt/reviewView examples

Storage and Filesystems · 35 commands

LVM Logical Volume Management Cheat Sheet

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Inventory physical volumessudo pvs -o \ pv_name,pv_uuid,vg_name,pv_size,pv_free,pv_attr,dev_sizeView examples
Inventory volume groupssudo vgs -o \ vg_name,vg_uuid,vg_size,vg_free,pv_count,lv_count,vg_attrView examples
Inventory logical volumessudo lvs -a -o \ lv_full_name,lv_size,segtype,lv_attr,origin,pool_lv,data_percent,metadata_percent,devicesView examples
Export a structured reportsudo lvm fullreport --reportformat json_stdView examples
Initialize a physical volumesudo pvcreate /dev/disk/by-id/wwn-0x5000c50012345678View examples
Create a volume groupsudo vgcreate vgdata \ /dev/disk/by-id/wwn-0x5000c50012345678View examples
Create a linear LVsudo lvcreate --name app --size 100G vgdataView examples
Extend an LV and filesystemsudo lvextend --resizefs --size +20G /dev/vgdata/appView examples
Consume remaining VG spacesudo lvextend --resizefs --extents +100%FREE \ /dev/vgdata/appView examples
Grow a mounted XFS filesystemsudo xfs_growfs /srv/appView examples
Test an LV reduction plansudo lvreduce --test --size 80G /dev/vgdata/archiveView examples
Reduce an LV after its filesystemsudo lvreduce --size 80G /dev/vgdata/archiveView examples
Create a thin poolsudo lvcreate --type thin-pool --name pool0 --size 500G \ vgdataView examples
Create a thin LVsudo lvcreate --type thin --name tenant1 --virtualsize \ 2T --thinpool vgdata/pool0View examples
Monitor thin-pool utilizationsudo lvs -o \ lv_full_name,segtype,lv_size,data_percent,metadata_percent,pool_lv,discardsView examples
Extend thin-pool datasudo lvextend --size +100G vgdata/pool0View examples
Extend thin-pool metadatasudo lvextend --poolmetadatasize +1G vgdata/pool0View examples
Create a COW snapshotsudo lvcreate --snapshot --name app-prechange --size 20G \ /dev/vgdata/appView examples
Monitor snapshot consumptionsudo lvs -o \ lv_full_name,origin,lv_size,data_percent,lv_attrView examples
Merge a snapshotsudo lvconvert --merge /dev/vgdata/app-prechangeView examples
Move extents between PVssudo pvmove /dev/disk/by-id/wwn-0x5000c50011111111 \ /dev/disk/by-id/wwn-0x5000c50022222222View examples
Remove an empty PV from a VGsudo vgreduce vgdata \ /dev/disk/by-id/wwn-0x5000c50011111111View examples
Tag a logical volumesudo lvchange --addtag production vgdata/appView examples
Select LVs by tagsudo lvs -o lv_full_name,lv_tags -S 'tags={production}'View examples
Activate one LVsudo lvchange --activate y vgdata/appView examples
Deactivate one LVsudo lvchange --activate n vgdata/appView examples
Disable LV autoactivationsudo lvchange --setautoactivation n vgdata/appView examples
Back up VG metadatasudo vgcfgbackup --file /var/backups/lvm/vgdata.conf \ vgdataView examples
List metadata archivessudo vgcfgrestore --list vgdataView examples
Test metadata restorationsudo vgcfgrestore --test --file \ /var/backups/lvm/vgdata.conf vgdataView examples
List the LVM devices filesudo lvmdevicesView examples
Check device-file entriessudo lvmdevices --checkView examples
Set thin-pool discard modesudo lvchange --discards nopassdown vgdata/pool0View examples
Report VG ownership and lockingsudo vgs -o \ vg_name,vg_uuid,vg_attr,vg_systemid,vg_locktypeView examples
Start shared-VG lockingsudo vgchange --lockstart vgsharedView examples

Storage and Filesystems · 20 commands

NFS and autofs Cheat Sheet

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UseSyntaxExamples
List NFS mountsfindmnt -t nfs,nfs4 -o TARGET,SOURCE,FSTYPE,OPTIONSView examples
Show negotiated optionsnfsstat --mountsView examples
Query NFSv3 exportsshowmount --exports nfs1.example.netView examples
List RPC servicesrpcinfo -p nfs1.example.netView examples
Mount NFSv4.1sudo mount -t nfs4 -o vers=4.1,sec=krb5p \ nfs1.example.net:/projects /srv/projectsView examples
Mount read-only for validationsudo mount -t nfs4 -o ro,vers=4.1 \ nfs1.example.net:/projects /mnt/nfs-testView examples
Unmount normallysudo umount /srv/projectsView examples
Identify mount userssudo fuser -vm /srv/projectsView examples
Show active exportssudo exportfs -vView examples
Reload exportssudo exportfs -raView examples
Validate export syntaxsudo exportfs -ravView examples
Show server statisticsnfsstat --serverView examples
Show client statisticsnfsstat --clientView examples
Inspect per-mount statisticsmountstats /srv/projectsView examples
Check autofs mapssudo automount --dumpmapsView examples
Reload autofssudo systemctl reload autofs.serviceView examples
Show automount unitsfindmnt -t autofs -o TARGET,SOURCE,OPTIONSView examples
Read autofs logsjournalctl -u autofs.service --since today --no-pagerView examples
Check NFSv4 id mappingnfsidmap -lView examples
Inspect GSS servicessystemctl status rpc-gssd.service rpc-svcgssd.service \ --no-pagerView examples

Storage and Filesystems · 20 commands

Samba File Sharing Cheat Sheet

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UseSyntaxExamples
Show Samba versionsmbd --versionView examples
Validate configurationtestparm --suppress-prompt /etc/samba/smb.confView examples
Inspect one sharetestparm --suppress-prompt --section-name projects \ /etc/samba/smb.confView examples
List configured servicestestparm --suppress-prompt --show-all-parameters \ /etc/samba/smb.confView examples
List server sharessmbclient --list=files1.example.net --user=aliceView examples
Open an SMB clientsmbclient //files1.example.net/projects --user=aliceView examples
Connect with Kerberossmbclient //files1.example.net/projects \ --use-kerberos=required --no-passView examples
Show active sessionssudo smbstatus --sharesView examples
Show locked filessudo smbstatus --locksView examples
Reload configurationsudo smbcontrol all reload-configView examples
Add a Samba passwordsudo smbpasswd -a aliceView examples
Disable a Samba accountsudo smbpasswd -d aliceView examples
Enable a Samba accountsudo smbpasswd -e aliceView examples
Read a share ACLsmbcacls //files1.example.net/projects / --user=aliceView examples
Read filesystem ACLsgetfacl --absolute-names /srv/samba/projectsView examples
Show protocol boundstestparm --suppress-prompt \ --parameter-name='server min protocol' \ /etc/samba/smb.confView examples
Show signing policytestparm --suppress-prompt \ --parameter-name='server signing' /etc/samba/smb.confView examples
Inspect SMB listenersss -ltnp 'sport = :445'View examples
Read smbd logsjournalctl -u smb.service -u smbd.service --since today \ --no-pagerView examples
Mount an SMB sharesudo mount -t cifs //files1.example.net/projects \ /mnt/projects -o \ credentials=/root/.smb-projects,vers=3.1.1View examples

Storage and Filesystems · 20 commands

Swap, zram, and Memory Pressure Cheat Sheet

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UseSyntaxExamples
Summarize memoryfree --human --wideView examples
Read kernel memory countersgrep -E \ '^(MemAvailable|SwapTotal|SwapFree|Dirty|Writeback|Slab|SReclaimable):' \ /proc/meminfoView examples
List swap areasswapon --show --output=NAME,TYPE,SIZE,USED,PRIOView examples
Read kernel swap tablecat /proc/swapsView examples
Sample reclaim and swappingvmstat 1 10View examples
Read memory PSIcat /proc/pressure/memoryView examples
Sample swap activitysar -W 1 10View examples
Rank processes by RSSps -eo pid,user,comm,rss,vsz --sort=-rss | head -20View examples
Inspect one process memorysudo cat /proc/1234/smaps_rollupView examples
Find OOM eventsjournalctl -k -g 'oom|Out of memory|Killed process' \ --since today --no-pagerView examples
Read swappinesssysctl vm.swappinessView examples
Read overcommit policysysctl vm.overcommit_memory vm.overcommit_ratioView examples
Enable prepared swapsudo swapon --priority 10 /swapfileView examples
Disable one swap areasudo swapoff /swapfileView examples
List zram deviceszramctl --output \ NAME,ALGORITHM,DISKSIZE,DATA,COMPR,TOTAL,STREAMS,MOUNTPOINTView examples
Read zram memory statscat /sys/block/zram0/mm_statView examples
Configure a zram devicesudo zramctl /dev/zram0 --algorithm zstd --size 4GView examples
Reset an unused zram devicesudo zramctl --reset /dev/zram0View examples
Read zswap statecat /sys/module/zswap/parameters/enabledView examples
Read cgroup memory eventscat \ /sys/fs/cgroup/system.slice/example.service/memory.eventsView examples
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