bfrie...@simple.dallas.tx.us said: > Your IOPS don't seem high. You are currently using RAID-5, which is a poor > choice for a database. If you use ZFS mirrors you are going to unleash a > lot more IOPS from the available spindles.
RAID-5 may be poor for some database loads, but it's perfectly adequate for this one (small data warehouse, sequential writes, and so far mostly sequential reads as well). So far the RAID-5 LUN has not been a problem, and it doesn't look like the low IOPS are because of the hardware, rather the database/application just isn't demanding more. Please correct me if I've come to the wrong conclusion here.... > I am not familiar with zilstat. Presumaby the '93' is actually 930 ops/ > second? I think you answered your question in your second post. But for others, the "93" is the total ops over the reporting interval. In this case, the interval was 10 seconds, so 9.3 ops/sec. > I have a 2540 here, but a very fast version with 12 300GB 15K RPM SAS drives > arranged as six mirrors (2540 is configured like a JBOD). While I don't run > a database, I have run an IOPS benchmark with random writers (8K blocks) and > see a peak of 3708 ops/sec. With a SATA model you are not likely to see > half of that. Thanks for the 2540 numbers you posted. There's a SAS 2530 here with the same 300GB 15kRPM drives, and as you said, it's fast. But it looks so far like the SATA model, even with less than half the IOPS, will be more than enough for our workload. I'm pretty convinced that the SATA 2540 will be sufficient. What I'm not sure of is if the cheaper J4200 without SSD would be sufficient. I.e., are we generating enough synchronous traffic that lack of NVRAM cache will cause problems? One thing zilstat doesn't make obvious (to me) is the latency effects of a separate log/ZIL device. I guess I could force our old array's cache into write-through mode and see what happens to the numbers. Judging by our experience with NFS servers using this same array, I'm reluctant to try. Thanks and regards, Marion _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
