Joe,
How did you measure response time of your SAN?


"Jochen Kaiser" <this.address@wont.work.com> wrote in message
news:c48pg4$k5f$1@news.sns-felb.debis.de...
> Hello,
>
> I'd like to verify whether the following situation can be considered
> 'normal'.
>
> Our databases (Solaris 8, DB2, UFS, 300GB OLTP and a 150GB DWH) are
> housed on a SAN array. (HDS9570V equipped with 146GB disks, McData
> switching in between, single hop, two FCs from host-side)
>
> I see (sar) very slow service times from the array, especially on those
> partitions housing our database-files. The response times (including
> queuing time) average at 50-100ms and peak at up to 500ms when we're
> loading data to the data warehouse or the OLTP.
> These scenarios result in lots of random reads on 4k and 16k tablespaces
> and a fair share of random writes in the same space-range. I'd expect a
> ratio of 15:1 concerning reads vs. writes.
>
> My Datacenter is telling me that they consider this situation normal,
> although they admit that the service times 'could be better'.
> We're sharing the array with a number of other applications, all of
> which fall into the OLTP category, but I'm unable to measure any
> performance increase during the night (when the OLTPs should be  silent).
>
> I'd expect that service times are much better, 20ms max.
>
> Is this a realistic assumption?
> What would you try to get as an agreed SL?
> Are service times like the ones above normal in your SAN?
>
>
> Many thanks in advance for you help,
>
> Jochen
>
>
>

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