K,

Thanks again for your comments. I guess we will need to disagree here because I believe that sophisticated caching can help subsystems perform better on SPC-1. I suppose it's not to much of a stretch to say that SPC-1 is "caching challenged". ;)

Ray

Calvin,

Thanks for the invite and the post links.

Ray

Thanks again for your comment.

I probably don't understand SVC as well as I should. It is only recently that SVC supported thinly provisioned storage behind it. The space efficient volumes ended up all being initialized before the test was begun. It's unclear to me whether at that time the whole Vdisk space was allocated and written or not. Most of todays thinly provisioned storage wouldn't write out an all zeros block to the storage just faking it if it was ever read. Which means that "real" allocation of storage to a thinly provisioned LUN would wait until actual data was written to it. So I still believe the SVC4.3s use of space efficient volumes and pre-formatting/pre-allocating all the space is not "true" thin provisioning but is more a mixed version of thin and fat provisioning. I guess we will have to disagree on this issue

However, with SSDs becoming more available they should boost performance considerably. Witness TMS results especially in LRT. But even so, disk based systems have the 7 of the top 10 IOPS results (see my detailed report in my newsletter). However, storage performance is hidden behind the system controllers. In order to tease out controller effectiveness with SSDs we would need some sort of IOPS/SSD level analysis. But with TMS having it's own SSDs, FusionIO or PCIe FLASH based systems showing up all over the place, and mixed SSD-disk drive systems becoming ever more prominant any IOPS/SSD becomes awfully complicated .

I am still not convinced that caching makes no difference to SPC-1 results. But that will need to wait for another post.

Ray

Storagebuddhist,

Thanks for the comment. I see where the SVC 4.3 used space efficient disks but then it populated all the blocks by initializing them. Not sure how I should consider this. However, it's unlikely that the backend storage (DS4700s) at the time were thin provisioned. So it's sort of a mixture between thinly provisioned at the SVC level and not at the storage subsystem level.

Nonetheless, it was a good catch.

Ray

K,

Thanks for the comment. I believe that SPC-1 is not that cache hostile anymore, or perhaps that subsystems are getting better at understanding it's "randomness". But that being said there does appear to be some more dispersion over 500 drive counts.

Ray

Paul,

Thanks for all the comments. A couple of points on your series of comments:

1) Yes, better or newer disks can help performance, but one reason I eliminate anything less than 140GB disks is that the older the disk, typically the smaller the capacity which provides a performance advantage by having more spindles. This chart tries to eliminate the spindle count advantage as much as I can. Without knowing the actual OEM vendor of the disks used in each SPC-1 benchmark, it would be very hard for me to try to level the playing field with similar disk performance. That being said, the HDS VSP did have SFF drives and as far as I can tell the T800 did not.

2) Dynamic provisioning, thin provisioning etc. should have some benefits and some performance costs. The benefits are probably subject for a different post but the performance costs should be evident from a sufficient set of benchmark results. There are plenty of storage systems that offer Thin provisioning but this is the first time I have seen one supply a benchmark result with it active. Kudos to HDS for being the first one to do so. All that being said, theoretically, thin provisioning should provide more data storage over less disks. Given that, I believe that from a performance per disk spindle basis it should perform better than a non-thinly provisioned system. To test this we would need equivalent systems one with thin provisioning active and one without. Alas, we don't have such a comparison available just yet

3) Thanks for providing the direct links to the two SPC-1reports.

4) As for unused capacity, it's a pretty complex issue and plays out, in the number of "extra" disks being used to support the workload, subsystem cost and $/IOPS. The purpose of the chart is to try to level the playing field, at least with respect to the number of disks, whether the capacity is "used" or "unused" plays no part in this chart.

5) I guess I don't see the host based RAID-0 striping configuration unless your talking about the TSC configuration section (~p.68). At best I see this as mapping the VSPs RAID-10 to the Windows host LUNs. While it does appear to be striping the host data across the VSP RAID10 LUNs, it's unclear whether this helps or hurts the performance. Although to be honest I am no Windows configuration expert.

Once again, thanks for the thoughtful comments.

Ray

Paul,
Ditto
Ray

Paul,
Good points...
Ray

Paul,

Thanks for your comments...

Ray

Greg,

Thanks for the comment and the proof point. Sounds like I need to get one. If only they had Mac support.

Ray