[PVE-User] LVM over ISCSI issue

[Amin Vakil]

Sorry, I just realized I've send my previous email with wrong subject.

> Looks like you are trying to clone an existing VM stored on the NFS server
> to the iSCSI target. Problem is that both the NFS server and iSCSI target
> are served by the same machine, so my best guess is that the I/O on the
> storage server is getting saturated. Have you tried creating a new VM on
> iSCSI instead ? Can you also try setting bandwidth limits at "Datacenter ->
> Options -> Bandwidth Limits" and then retry cloning operation ?
> 

I cloned to nfs to make sure it's ok, it doesn't make any difference
when cloning from local or nfs to iscsi. the problem is the same, here
is the log cloning from local to iscsi: http://ix.io/2tRX

Also sometimes it errors in the middle of cloning process: http://ix.io/2tRV

Creating a vm and adding a disk on iscsi to an existing vm is fine.

I have set bandwidth limits and it didn't make any difference.

>>> kernel: blk_update_request: I/O error, dev sdb, sector 1762240503 op
> 0x9:(WRITE_ZEROES) flags 0x0 phys_seg 0 prio class 0
> 
> Is this on the storage server or the PVE host ? What does /dev/sdb
> represent in this case ? if it's a hard drive, it looks like it's having
> some hw issues ? Better to test with smartctl if that's the case.

The storage server is a qnap NAS, and it's health and smart is
constantly monitored. Of course faulty hardware can never be ruled out
completely, but I doubt that would be the case, because qnap smart
status and hard health is ok and none of the running VMs on iscsi are
facing any issue.

fdisk -l:
...
Disk /dev/sdb: 3.9 TiB, 4294967296000 bytes, 8388608000 sectors
Disk model: iSCSI Storage
...

iscsiadm -m session -P 2:
http://ix.io/2tRY (ip address and username have been changed, everything
else are unchanged)

Although I have cloned to iscsi now, but it succeed after trying many
times, the error seems to be random.

Also if it helps someone on ##proxmox IRC told me this:
it basically fails at the sparse scsi command
WRITE_ZEROES
that is _usually_ an array issue



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