Rokka, this really isn't a ZFS problem. 8 SATA disks in a raid-z2 or raid-6 array is going to be horible for eith exchange or SQL, let alone both running together.
ZFS has a lot of flexibility, and a lot of tools that will let you run these systems off one pool, but you really need to do a lot more research on the different performance aspects of different raid levels. To give a quick example: raid-6 or raid-z2 gives high throughput, but low iops. Your 8 drives can stream data at around 6x the speed of a single drive, but when it comes to iops it's no faster than a single disk. A 4x2 raid10 set of mirrors gives completely different performance. Yes, you loose space, that is the tradeoff you get for higher performance. In this configuration you can write at 4x the speed of a single disk (since writes will be striped over the 4 sets). Individual reads can run at 1-8x the speed, depending on how many disks they are striped across. However it's iops where things really improve. You have write performance of 4x the iops of a single disk, and read performance of 8x. So for iops bound loads such as exchange or sql, using raid10 with your disks will be 4-8x faster than raid-6 / raid-z2. And don't assume that SSD's will automatically fix the problem. Yes, they can bring a massive improvement but they are even more complicated than disks in terms of performance. You need to understand sequential and random read & write speeds, and the speed at different block sizes. An SSD that can perform very fast random reads might be horribly slow for writes, and wind up giving you worse performance than your disk array. You also have to consider the interface to your server. If you're running over iscsi, you are probably limited to 90MB/s throughput at best. A single physical disk can go faster than that so it's unlikely you're even seeing the throughput benefits of your raid array. -- This message posted from opensolaris.org _______________________________________________ storage-discuss mailing list [email protected] http://mail.opensolaris.org/mailman/listinfo/storage-discuss
