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From: ianwr on 10 Dec 2007 08:22
One very interesting point to note, i did the same on an identical
server that is running sql 2000 rather than 2005, according to the san
guy its setup identical and the performance times were very different.

throughput was 80mb/sec rather than 20mb/sec and latency was 30ms
rather than the 600-700ms. I tried 3 or 4 times with the same query
and results were constant.

Gone back to the SAN guy and asked him to confirm everything was
identical. If he says they are will run SQLio on the server to confirm
if SQL server is the culprit or the configurations are indeed
different.


Ian,
From: TheSQLGuru on 10 Dec 2007 11:01
There is definitely something different somewhere. It could possibly be
linked to OS file level fragmentation, but I doubt that could be the sole
reason for that level of throughput/latency issues.

--
Kevin G. Boles
TheSQLGuru
Indicium Resources, Inc.


"ianwr" <ianwrigglesworth(a)yahoo.co.uk> wrote in message
news:61d00455-495f-428a-9fa4-4712d861933b(a)x69g2000hsx.googlegroups.com...
> One very interesting point to note, i did the same on an identical
> server that is running sql 2000 rather than 2005, according to the san
> guy its setup identical and the performance times were very different.
>
> throughput was 80mb/sec rather than 20mb/sec and latency was 30ms
> rather than the 600-700ms. I tried 3 or 4 times with the same query
> and results were constant.
>
> Gone back to the SAN guy and asked him to confirm everything was
> identical. If he says they are will run SQLio on the server to confirm
> if SQL server is the culprit or the configurations are indeed
> different.
>
>
> Ian,


From: TheSQLGuru on 10 Dec 2007 11:02
Disk sec/read is extraordinarily high. You don't need a sqlio run to give
something to the SAN guys IMHO. 700-1200ms latency is way more than enough.

--
Kevin G. Boles
TheSQLGuru
Indicium Resources, Inc.


"ianwr" <ianwrigglesworth(a)yahoo.co.uk> wrote in message
news:e608dedf-961a-48cd-b53f-60df4df1d1ec(a)e67g2000hsc.googlegroups.com...
> Guys,
>
> Just a quick update on the performance, here are the performance
> counters i took this morning running the table scan again :-
>
> Disk Rad Bytes.Sec = between 11m and 33m was very choppy. so i guess
> this is about 10 times too slow as it's on average about 20mb/sec
> rather than the 200mb you were expecting.
>
> Avg Disk Bytes/Read was around the 77k mark
>
> Avg Disk Sec/Read was around the 0.7 mark but at times went upto
> 1.2 ... pretty shocking. Going to get sqlio on the job and see if we
> can get some timing to go back to the SAN guys with.
>
> Ian.
>
>
>


From: ianwr on 10 Dec 2007 11:56
Will keep you posted and let you know what it was when i get to the
bottom of it.

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