April 6, 2004 at 3:24 pm
Hi guys,
I have a quite large SAP database of 250+GB.
We are planning to implement the SAP IS-U (the utility module of SAP). therefore we expect the datbase size to be between 2-3TB within 2 years.
At the beginning we have used a HP MA8000 storage to store the data. Because we have got a lot of stability problems (The local HP seems to have some problem to stabilize it) we have decided to move our database to IBM ESS (aka Shark).
Altough this is a much more expensive device it comes out that the response times are much slower on the Shark, then on the MA8000, especially on read activities. In the perfmon I have an incredible high number of Avg disk queue value.
My question to you is: what kind of disk subsystem would you recommend (a product maybe?) for that kind of database size.
As of today we have (or we have got on the MA8000) an average response time of 0,5 sec/transaction.
Thanks
Bye
Gabor
April 6, 2004 at 8:54 pm
Hi Gabor,
Had Similar issues with our Data Warehouse, decided to go for a mixed solution consisting of Direct Attached Disk and an IBM FastT 700 SAN. (Tried ESS Shark but could not get the performance)
Our Database is approx. 1TB and grow by 10GB per month.
The Direct attached drives allowed us to configure Raid arrays to meet specfic disk bottlenecks i.e. core tables had their own filegroups on there own arrays, indexes had own arrays etc. This allowed us to tune the IO subsystem specifically for our database and use.
The FastT 700 SAN was used for backup and slower tables.
In order to get maximum performance we are using an IBM 445 server with an RXE expansion unit which provides an additonal 2GB bandwidth to the PCI X Bus. this allows 6 dual channel SCSI controllers and 4 Fibre cards.
This design took several iterations to achieve, started off by specifiying tables that were bottlenecks etc and based on our budget came up with the best solution.
Hope this helps, If you would like specifics etc please ask.
April 7, 2004 at 5:48 am
Brandon,
Thanks for reply.
My concern with the DAS is that it's not usable for a cluster. Anyhow I have to use an external disk subsystem and attach my two nodes to it (thru FC switches).
I would use as many, as fast and as small drives as I can. So I would need a container which can contain a lot of disks (160 pieces of 36GB disks make a bit more then 3TB in RAID 1). IO performance is a key issue here because the SAP IS-U runs a lot of batches which moves a big quantity of data every day.
Bye
Gabor
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