Hi All,

I was wondering if anyone has seen poor performance when using the
HDLM drivers with a Hitachi SAN.

This is what we have:
AIX 5.2 ML3
HITACHI Thunder 9500
HDLM 5.1.1.2 (DLManager.rte)

What we see is constant high I/O waits. We have 8 GB of memory on this
server and it is running a CACHE database. Although we see some Pagin
activity (pi/po) sometimes, the I/O wait can get to 60 % sometimes.
When the activity is not ver high, we see about 30 to 45 %.

Has anyone experienced or seen this before?

Thanks in advance,

BTNA

btna wrote:
> Hi All,
>
> I was wondering if anyone has seen poor performance when using the
> HDLM drivers with a Hitachi SAN.
>
> This is what we have:
> AIX 5.2 ML3
> HITACHI Thunder 9500
> HDLM 5.1.1.2 (DLManager.rte)
>
> What we see is constant high I/O waits. We have 8 GB of memory on
this
> server and it is running a CACHE database. Although we see some Pagin
> activity (pi/po) sometimes, the I/O wait can get to 60 % sometimes.
> When the activity is not ver high, we see about 30 to 45 %.
>
> Has anyone experienced or seen this before?
>

Post some vmstat and iostat output, I've run HDLM drivers on EXTREMELY
busy machines and the bottle neck was never the driver. You may need
to adjust the queue_depth (lsattr -El dlmdrv##) on the disks however.
There may be some AIX tuning as well.


--
Dana French