Hi,
We have an oldish HP MSA p2000 g3 iscsi as a backup target.
Yesterday I enabled MPIO to get more troughput since our backups are gettin quite big.
I ran in to problems. First, my archive backups vere corrupted. After that I formatted the volume and send backups there again. During the night server has bsod'ed and in morning the whole volume was not readable and windows is asking to forma it. I think I might have an fundamental error in my mpio config. The archive volume has windows deduplication enabled.
The setup is following:
I have 24x900gb disks in two raid6 vdisks.
Management interfaces are assigned to 192.168.100.0 network.
A1 and B1 port has been assigned to 192.168.100.0 network
A2 and B2 port has been assigned to 10.100.11.0 network
Backup server is running win2012 r2
Nic1 has been assigned to 192.168.100.0 network
Nic2 has been assigned to 10.100.11.0 network
MPIO is enabled in windows server.
connecting to storage:
From backup server, start iscsi initiator
go to discovery tab, click discover portal
enter A1 port ip address, OK
go to targets tab, Storage now appears in "discovered targets".
Click connect and Properties.
Click add session, select enable multi-path, click advanced. Select "Microsoft iSCSI Initiator" as local adapter, Nic1 IP as initiator IP, B1 ip as target IP.
Add two more sessions like above, Nic2 -> A1, Nic2 -> B2.
At properties, click devices -> MPIO -> select Least Queue Depth as load balance policy.
Close everything and start computer management.
Under disk drives, I now have two HP P2000 G3 iSCSI Multi-Path Disk Devices.
Right click -> properties, uncheck "Enable write caching on the device", go to MPIO tab, select Least Queue Depth for MPIO Policy. Repeat for another disk.
Some observations, that puzzles me.
When I now copy large files over iSCSI, the copy is extremely fast. However, it seems that the file is actually being cached in the memory and after the copy "finishes", it is actually still being transferred for tens of seconds (observed from task manager -> performance).
For some reason in isci initiator -> target -> properties, in the sessions tab, in the identifiers, some of the identifiers has Data Digest automatically set to "CRC32", some has "None Specified". Also, since this morning I now have five identifiers. Nic1 -> B2 seems to be double.
Some questions:
Is it ok to have multiple storage ports in the same subnet or should each port be in its own subnet? Is it ok to have iSCSI ports in the same subnet than management ports?
In iscsi initiator, in discovery tab, should I add each IP address to target portals or only A1, or A1 and B1?
In isci initiator target -> properties -> Should I add so many sessions, or just have Nic1 -> A1 and Nic2 -> B2 or something else?
In the device manager, is it OK to disable caching, for maximum stability?
Thanks in advance, please ask for more detail if needed.
E:typos