Low I/O speed AX4-5

How many paths are there from the AX to the server?

Does PowerPath see all the paths zoned?

Have you tried using the default 1500 for MTU to test?

glen

I see al my 4 paths in powerpath

I tried it with mtu 1500 and 9000 but that wasn't a solution.

SAN is connected with 2 cisco switches with there own range
Server is connected with bought switches

172.20.10.1
and
172.20.11.1

I tried it with the next policy:

ClarOPT with 4 connected--> slow quick format (30min/60min for 100GB)
LeastIO --> fast quick format
Leastblocks --> fast quick format
Round Robin --> fast quick format

But whit all above policy's i only have a copy speed of max 25mb sec when copying from a lun to another lun at the same windows 2008 host.

Copying files from a lun to a lun at another windows 2008 server is with a speed of 50/120mb sec.

But i think it must be much faster.

on the windows 2008 server, open the iSCSI Initiator Control Panel, go to the Favorites tab and select one of the paths lists - you should see four paths here - click on Details and you should see a list of the connection details - find the "Source IP" entry - what is the value - it should be one of the iSCSI NIC's on the server - if it is listed as "Default" then you need to re-do your connections - see the attached PDF for fixing this type of issue. This was written for Windows 2003, but is work for 2008 - the tab called Persistent Binding is now called Favorites in 2008 (go figure).

glen

Whe tought that it was the solution, but when we copy files at the same host from Lun to Lun, the copy speed falls to 10mb sec.

We use iSCSI
Lun 1 is on Raid group 0 SATA disks Raid 5
Lun 2 is on Raid group 1 SAS disks Raid 5

Can someone help?

How many disks are in each raid group? There is a performance difference between SATA and SAS. SATA can run about about 6MB/s per disk. SAS (if 10K RPM) can run at about 10MB/s per disk.

If you copy from the SAS and write to the SATA, you may be filling up Write cache as you can read from SAS quite a bit faster than you can write to SATA. But even with this speed difference you should still be able to write more than 10MB/s to SATA disks in a Raid 5 (assuming that you have a 4+1)

How many paths from the host to they array?

How many NIC's are on the server? If you have three NIC's I assume that your using two for iSCSI. Are the iSCSI on a separate network or VLAN? Can you check on the switch and see if you have a lot of frame discards?

If you have two NIC configured to four ports on the array, are they configured similar to below:

NIC1 <--> SPA 0
NIC1 <--> SPB 0
NIC2 <--> SPA 1
NIC2 <--> SPA 2

what do you get when you run the following on the server:

powermt display dev=all

If you are seeing a lot of frame discards on the switch try removing two of the paths - you can log off in the iSCSI Initiator:

NIC1 <--> SPA 0
NIC2 <--> SPB 0

glen