Disks

Checks your disks 1# check partion 2parted -l /dev/sda 3fdisk -l 4 5# check partition - visible before the mkfs 6ls /sys/sda/sda* 7ls /dev/sd* 8 9# give partition after the mkfs or pvcreate 10blkid 11blkid -o list 12 13# summary about the disks, partitions, FS and LVM 14lsblk 15lsblk -f Create Partition 1 on disk sdb in script mode 1# with fdisk 2printf "n\np\n1\n\n\nt\n8e\nw\n" | sudo fdisk "/dev/sdb" 3 4# with parted 5sudo parted /dev/sdb mklabel gpt mkpart primary 1 100% set 1 lvm on Gparted : interface graphique (ce base sur parted un utilitaire GNU - Table GPT)

The Basics mdadm (multiple devices admin) is software solution to manage RAID. It allow: create, manage, monitor your disks in an RAID array. you can the full disks (/dev/sdb, /dev/sdc) or (/dev/sdb1, /dev/sdc1) replace or complete raidtools Checks Basic checks 1# View real-time information about your md devices 2cat /proc/mdstat 3 4# Monitor for failed disks (indicated by "(F)" next to the disk) 5watch cat /proc/mdstat Checks RAID 1# Display details about the RAID array (replace /dev/md0 with your array) 2mdadm --detail /dev/md0 3 4# Examine RAID disks for information (not volume) similar to --detail 5mdadm --examine /dev/sd* Settings The conf file /etc/mdadm.conf does not exist by default and need to be created once you finish your install. This file is required for the autobuild at boot.

FS Types ext4 : le plus répandu sous GNU/Linux (issu de ext2 et ext3). Il est journalisé, c’est à dire qu’il trace les opérations d’écriture pour garantir l’intégrité des données en cas d’arrêt brutal du disque. De plus, il peut gérer des volumes de taille jusque 1 024 pébioctets et permet la pré-allocation d’une zone contiguë pour un fichier, afin de minimiser la fragmentation. Utilisez ce système de fichiers si vous comptez pouvoir relire des informations depuis votre Mac OS X ou Windows.

S.M.A.R.T. is a technology that allows you to monitor and analyze the health and performance of your hard drives. It provides valuable information about the status of your storage devices. Here are some useful commands and tips for using S.M.A.R.T. with smartctl: Display S.M.A.R.T. Information To display S.M.A.R.T. information for a specific drive, you can use the following command: 1smartctl -a /dev/sda This command will show all available S.M.A.R.T. data for the /dev/sda drive.

Install 1yum install iscsi-initiator-utils 2 3#Checks 4iscsiadm -m session -P 0 # get the target name 5iscsiadm -m session -P 3 | grep "Target: iqn\|Attached scsi disk\|Current Portal" 6 7# Discover and mount ISCSI disk 8iscsiadm -m discovery -t st -p 192.168.40.112 9iscsiadm --mode discovery --type sendtargets --portal 192.168.40.112 10 11# Login 12iscsiadm -m node -T iqn.1992-04.com.emc:cx.ckm00192201413.b0 -l 13iscsiadm -m node -T iqn.1992-04.com.emc:cx.ckm00192201413.b1 -l 14iscsiadm -m node -T iqn.1992-04.com.emc:cx.ckm00192201413.a1 -l 15iscsiadm -m node -T iqn.1992-04.com.emc:cx.ckm00192201413.a0 -l 16 17# Enable/Start service 18systemctl enable iscsid iscsi && systemctl stop iscsid iscsi && systemctl start iscsid iscsi Rescan BUS 1for BUS in /sys/class/scsi_host/host*/scan; do echo "- - -" > ${BUS} ; done 2 3sudo sh -c 'for BUS in /sys/class/scsi_host/host*/scan; do echo "- - -" > ${BUS} ; done ' Partition your FS

Install and Set Multipath 1yum install device-mapper-multipath Check settings in vim /etc/multipath.conf: 1defaults { 2user_friendly_names yes 3path_grouping_policy multibus 4} add disk in blacklisted and a block 1multipaths { 2 multipath { 3 wwid "36000d310004142000000000000000f23" 4 alias oralog1 5 } Special config for some providers. For example, recommended settings for all Clariion/VNX/Unity class arrays that support ALUA: 1 devices { 2 device { 3 vendor "DGC" 4 product ".*" 5 product_blacklist "LUNZ" 6 : 7 path_checker emc_clariion ### Rev 47 alua 8 hardware_handler "1 alua" ### modified for alua 9 prio alua ### modified for alua 10 : 11 } 12 } Checks config with: multipathd show config |more

The Basics list of component: PV (Physical Volume) VG (Volume Group) LV (Logical Volume) PE (Physical Extend) LE (Logical Extend) FS (File Sytem) LVM2 use a new driver, the device-mapper allow the us of disk´s sectors in different targets: - linear (most used in LVM). - stripped (stripped on several disks) - error (all I/O are consider in errors) - snapshot (allow snapshot async) mirror (integrate elements usefull for pvmove commande) below example show you a striped volume and linear volume 1lvs --all --segments -o +devices 2server_xplore_col1 vgdata -wi-ao---- 21 striped 1.07t /dev/md2(40229),/dev/md3(40229),/dev/md4(40229),/dev/md5(40229),… 3server_xplore_col2 vgdata -wi-ao---- 1 linear 219.87g /dev/md48(0) Basic checks 1# Summary 2pvs 3vgs 4lvs 5 6# Scanner 7pvscan 8vgscan 9lvscan 10 11# Details info 12pvdisplay [sda] 13pvdisplay -m /dev/emcpowerd1 14vgdisplay [vg_root] 15lvdisplay [/dev/vg_root/lv_usr] 16 17# Summary details 18lvmdiskscan 19 /dev/sda1 [ 600.00 MiB] 20 /dev/sda2 [ 1.00 GiB] 21 /dev/sda3 [ 38.30 GiB] LVM physical volume 22 /dev/sdb1 [ <100.00 GiB] LVM physical volume 23 /dev/sdc1 [ <50.00 GiB] LVM physical volume 24 /dev/sdj [ 20.00 GiB] 25 1 disk 26 2 partitions 27 0 LVM physical volume whole disks 28 3 LVM physical volumes Usual Scenario in LVM Extend an existing LVM filesystem: 1parted /dev/sda resizepart 3 100% 2udevadm settle 3pvresize /dev/sda3 4 5# Extend a XFS to a fixe size 6lvextend -L 30G /dev/vg00/var 7xfs_growfs /dev/vg00/var 8 9# Add some space to a ext4 FS 10lvextend -L +10G /dev/vg00/var 11resize2fs /dev/vg00/var 12 13# Extend to a pourcentage and resize automaticly whatever is the FS type. 14lvextend -l +100%FREE /dev/vg00/var -r Create a new LVM filesystem: 1parted /dev/sdb mklabel gpt mkpart primary 1 100% set 1 lvm on 2udevadm settle 3pvcreate /dev/sdb1 4vgcreate vg01 /dev/sdb1 5lvcreate -n lv_data -l 100%FREE vg01 6 7# Create a XFS 8mkfs.xfs /dev/vg01/lv_data 9mkdir /data 10echo "/dev/mapper/vg01-lv_data /data xfs defaults 0 0" >> /etc/fstab 11mount -a 12 13# Create an ext4 14mkfs.ext4 /dev/vg01/lv_data 15mkdir /data 16echo "/dev/mapper/vg01-lv_data /data ext4 defaults 0 0" >> /etc/fstab 17mount -a Remove SWAP: 1swapoff -v /dev/dm-1 2lvremove /dev/vg00/swap 3vi /etc/fstab 4vi /etc/default/grub 5grub2-mkconfig -o /boot/efi/EFI/redhat/grub.cfg 6grubby --remove-args "rd.lvm.lv=vg00/swap" --update-kernel /boot/vmlinuz-3.10.0-1160.71.1.el7.x86_64 7grubby --remove-args "rd.lvm.lv=vg00swap" --update-kernel /boot/vmlinuz-3.10.0-1160.el7.x86_64 8grubby --remove-args "rd.lvm.lv=vg00/swap" --update-kernel /boot/vmlinuz-0-rescue-cd2525c8417d4f798a7e6c371121ef34 9echo "vm.swappiness = 0" >> /etc/sysctl.conf 10sysctl -p Move data form disk to another: 1# #n case of crash, just relaunch pvmove without arguments 2pvmove /dev/emcpowerd1 /dev/emcpowerc1 3 4# Remove PV from a VG 5vgreduce /dev/emcpowerd1 vg01 6 7# Remove all unused PV from VG01 8vgreduce -a vg01 9 10# remove all PV 11pvremove /dev/emcpowerd1 mount /var even if doesn’t want: 1lvchange -ay --ignorelockingfailure --sysinit vgroot/var Renaming: 1# VG rename 2vgrename 3 4# LV rename 5lvrename 6 7# PV does not need to be rename LVM on partition VS on Raw Disk Even if in the past I was using partition MS-DOS disklabel or GPT disklabel for PV, I prefer now to use directly LVM on the main block device. There is no reason to use 2 disklabels, unless you have a very specific use case (like disk with boot sector and boot partition).

The Basics NFS vs iscsi NFS can handle simultaniously writing from several clients. NFS is a filesystem , iscsi is a block storage. iscsi performance are same with NFS. iscsi will appear as disk to the OS, not the case for NFS. Concurrent access to a block device like iSCSI is not possible with standard file systems. You’ll need a shared disk filesystem (like GFS or OCSFS) to allow this, but in most cases the easiest solution would be to just use a network share (via SMB/CIFS or NFS) if this is sufficient for your application.

Server Side First Install samba and samba-client (for debug + test) /etc/samba/smb.conf 1[home] 2Workgroup=WORKGROUP (le grp par defaul sur windows) 3Hosts allow = ... 4[shared] 5browseable = yes 6path = /shared 7valid users = user01, @un_group_au_choix 8writable = yes 9passdb backend = tdbsam #passwords are stored in the /var/lib/samba/private/passdb.tdb file. Test samba config testparm /usr/bin/testparm -s /etc/samba/smb.conf smbclient -L \192.168.56.102 -U test : list all samba shares available smbclient //192.168.56.102/sharedrepo -U test : connect to the share pdbedit -L : list user smb (better than smbclient)

SSHFS SshFS sert à monter sur son FS, un autre système de fichier distant, à travers une connexion SSH, le tout avec des droits utilisateur. L’avantage est de manipuler les données distantes avec n’importe quel gestionnaire de fichier (Nautilus, Konqueror, ROX, ou même la ligne de commande). - Pre-requis : droits d'administration, connexion ethernet, installation de FUSE et du paquet SSHFS. - Les utilisateurs de sshfs doivent faire partie du groupe fuse. Rq : FUSE permet à un utilisateur de monter lui-même un système de fichier. Normalement, pour monter un système de fichier, il faut être administrateur ou que celui-ci l’ait prévu dans « /etc/fstab » avec des informations en dur.

Tar - « tape archiver » Preserve files permissions and ownership. The Basic 1# Archive 2tar cvf mon_archive.tar <fichier1> <fichier2> </rep/doosier/> 3 4## Archive and compress with zstd everything in the current dir and push to /target/dir 5tar -I zstd -vcf archive.tar.zstd -C /target/dir . 6 7# Extract 8tar xvf mon_archive.tar 9 10# Extract push to target dir 11tar -zxvf new.tar.gz -C /target/dir Other usefull options • t : list archive’s content. • T : Archive list given by a file. • P : Absolute path is preserve (usefull for backup /etc) • X : exclude • z : compression Gunzip • j : compression Bzip2 • J : compression Lzmacd