On Fri, 2009-07-03 at 08:50 +0100, Nick Lunt wrote: > Hi folks > > > > anyone running Oracle with iSCSI ? Were getting 8MB/s max throughput > with Oracle 10gR2.
8MB/s throughput doing what exactly? If this is the speed you're seeing when doing full tables scans, or backups, or other things like that, well, then you have a problem. If this is the performance you're seeing when doing single block reads (i.e. db_file_sequential_read) then based on the block size of your database you're most likely IOP limited. How many spindles? What's you Oracle block size, read latency, and total IOP capacity. We run multiple Oracle databases on Equallogic iSCSI SAN, fairly small (250GB) but reasonably transactional (Oracle eBusiness 11i) and pretty small block size (8K). Our production Equallogic array is 15K RPM SAS drives and performance is about 20% faster than what we used to see with our EMC Clariion fiber channel solution (10K RPM drives, but more of them). If you're doing single block reads (db_file_sequential_read, i.e. index scan by ROWID) you will be drastically limited by number of spindles and the read latency of your array. For example, if your block size is 8K, and average read latency is 1ms (which is pretty fast for spinning media), then you can read at most 1000 blocks per second or about 8MB/sec. Of course that's assuming only a single query, multiple query's will likely perform better since requests can be merged. Later, Tom _______________________________________________ rhelv5-list mailing list [email protected] https://www.redhat.com/mailman/listinfo/rhelv5-list
