Just got an interesting benchmark. I made two zpools:
RAID-10 (9x 2-way RAID-1 mirrors: 18 disks total) RAID-Z2 (3x 6-way RAIDZ2 group: 18 disks total) Copying 38.4GB of data from the RAID-Z2 to the RAID-10 took 307 seconds. Deleted the data from the RAID-Z2. Then copying the 38.4GB of data from the RAID-10 to the RAID-Z2 took 258 seconds. Would have expected the RAID-10 to write data more quickly. Its interesting to me that the RAID-10 pool registered the 38.4GB of data as 38.4GB, whereas the RAID-Z2 registered it as 56.4. Best Regards, Jason On 1/3/07, Jason J. W. Williams <[EMAIL PROTECTED]> wrote:
Hi Richard, Hmm....that's interesting. I wonder if its worth benchmarking RAIDZ2 if those are the results you're getting. The testing is to see the performance gain we might get for MySQL moving off the FLX210 to an active/passive pair of X4500s. Was hoping with that many SATA disks RAIDZ2 would provide a nice safety net. Best Regards, Jason On 1/3/07, Richard Elling <[EMAIL PROTECTED]> wrote: > Jason J. W. Williams wrote: > > Hello All, > > > > I was curious if anyone had run a benchmark on the IOPS performance of > > RAIDZ2 vs RAID-10? I'm getting ready to run one on a Thumper and was > > curious what others had seen. Thank you in advance. > > I've been using a simple model for small, random reads. In that model, > the performance of a raidz[12] set will be approximately equal to a single > disk. For example, if you have 6 disks, then the performance for the > 6-disk raidz2 set will be normalized to 1, and the performance of a 3-way > dynamic stripe of 2-way mirrors will have a normalized performance of 6. > I'd be very interested to see if your results concur. > > The models for writes or large reads are much more complicated because > of the numerous caches of varying size and policy throughout the system. > The small, random read workload will be largely unaffected by caches and > you should see the performance as predicted by the disk rpm and seek time. > -- richard >
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