Hard Disk problem

AntoWkill

Member
Jul 31, 2013
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Hello,
I have buy from ovh a server with 3x2000gb of disk, on proxmox i see only the first disk i have try to add the other with the command: pvcreate /dev/sdc1 or (sda1 etc) but i have an error: Device /dev/sdc1 not found (or ignored by filtering). or other error with the other disk: Can't open /dev/sdc4 exclusively. Mounted filesystem?

How i can add other Disk?
 
Never used OVH, but you have to enable RAID in BIOS if you want to see your 3x2T as a single 4T RAID5 disk. It have to be *real* RAID, not fake-raid. If you already used BIOS to create a RAID and still Proxmox sees the single drives, then your server only offers fake raid and you're toast (*).
Try posting 'mount' output. If you did a plain Proxmox install, then only the first disk is used (unless you set the three disks as a single one for RAID). The other two are neither partitioned nor formatted, so you can't use 'em till you run at least an fdisk (or parted) command.

(*) well, actually you could setup software RAID on the remaining drives, keeping the "free" space on the first drive for not-critical data, like ISO images.
 
root@ns321560:~# mount
sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime)
proc on /proc type proc (rw,nosuid,nodev,noexec,relatime)
udev on /dev type devtmpfs (rw,relatime,size=10240k,nr_inodes=16499419,mode=755)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)
tmpfs on /run type tmpfs (rw,nosuid,noexec,relatime,size=13201560k,mode=755)
/dev/md2 on / type ext3 (rw,relatime,errors=remount-ro,user_xattr,acl,barrier=0,data=ordered)
tmpfs on /run/lock type tmpfs (rw,nosuid,nodev,noexec,relatime,size=5120k)
tmpfs on /run/shm type tmpfs (rw,nosuid,nodev,noexec,relatime,size=27031620k)
fusectl on /sys/fs/fuse/connections type fusectl (rw,relatime)
/dev/mapper/pve-data on /var/lib/vz type ext3 (rw,relatime,errors=continue,user_xattr,acl,barrier=0,data=ordered)
rpc_pipefs on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw,relatime)
/dev/fuse on /etc/pve type fuse (rw,nosuid,nodev,relatime,user_id=0,group_id=0,default_permissions,allow_other)
none on /sys/kernel/config type configfs (rw,relatime)
beancounter on /proc/vz/beancounter type cgroup (rw,relatime,blkio,name=beancounter)
container on /proc/vz/container type cgroup (rw,relatime,freezer,devices,name=container)
fairsched on /proc/vz/fairsched type cgroup (rw,relatime,cpuacct,cpu,cpuset,name=fairsched)
 
root@ns321560:~# mount
sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime)
proc on /proc type proc (rw,nosuid,nodev,noexec,relatime)
udev on /dev type devtmpfs (rw,relatime,size=10240k,nr_inodes=16499419,mode=755)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)
tmpfs on /run type tmpfs (rw,nosuid,noexec,relatime,size=13201560k,mode=755)
/dev/md2 on / type ext3 (rw,relatime,errors=remount-ro,user_xattr,acl,barrier=0,data=ordered)
tmpfs on /run/lock type tmpfs (rw,nosuid,nodev,noexec,relatime,size=5120k)
tmpfs on /run/shm type tmpfs (rw,nosuid,nodev,noexec,relatime,size=27031620k)
fusectl on /sys/fs/fuse/connections type fusectl (rw,relatime)
/dev/mapper/pve-data on /var/lib/vz type ext3 (rw,relatime,errors=continue,user_xattr,acl,barrier=0,data=ordered)
rpc_pipefs on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw,relatime)
/dev/fuse on /etc/pve type fuse (rw,nosuid,nodev,relatime,user_id=0,group_id=0,default_permissions,allow_other)
none on /sys/kernel/config type configfs (rw,relatime)
beancounter on /proc/vz/beancounter type cgroup (rw,relatime,blkio,name=beancounter)
container on /proc/vz/container type cgroup (rw,relatime,freezer,devices,name=container)
fairsched on /proc/vz/fairsched type cgroup (rw,relatime,cpuacct,cpu,cpuset,name=fairsched)



My Hard Disk is raid Software
 
From my experience, RAID on system disk (in particular boot disk) is troublesome.
If the boot disk dies, you might be left with an unbootable system (if you upgraded grub and forgot to install the new code on the secondary disk, just to say what already happened...). Sure, you can recover, but it usally takes way more time than reinstalling from scratch and restoring the configs from a backup (because you need a backup anyway, to be sure -- at least for production hosts).
Said that, everybody if free to suffer as he wishes :)

How is your /dev/md2 configured (Raid level, number of disks...) ?
Is /dev/sdc already partitioned? If not, that's why you can't access sdc1.

With 3 drives and a sw-RAID1 for /, there are various partitioning schemes that could apply:
- maximum protection for system, balanced protection/space for data: RAID1 for / spanning all three disks, RAID5 of the remaining space
- no protection for system, good protection for data: no RAID for /, RAID1 of sdb and sdc, free space on sda used for ISO images, backups, etc (non-critical data)
- maximum protection: RAID1 on 3 disks (same space as having only one drive!)
- balanced: RAID1 on sda and sdb for /, same size of system data on sdc to be used for ISOs, backups, etc, RAID5 of the remaining space spanning 3 drives
(obviously more schemes are possible).

PS: IIRC it's sub-optimal to have swap on sw-RAID. Just create separate swap partitions on the drives and it's more efficient than a RAID0. No need to RAID1 the swap, usually.