On 18-07-11 02:35 PM, David Blundell wrote:
Hi, I’m looking at 4TB Intel DC P4510 for data drives running BlueStore with WAL, DB and data on the same drives. Has anyone had any good / bad experiences with them? As Intel’s new data centre NVMe SSD it should be fast and reliable but then I would have thought the same about the DC S4600 drives which currently seem best to avoid… David
tl;dr - try to avoid TLC NAND flash at all costs if consistent write performance is your target.
Lately I was benchmarking Intel DC P4500 (not DC P4510, mind you) and I easily ran into performance issues. Both DC P4500 and DC P4510 utilize 3d TLC NAND flash chips, so you won't get great speeds on very low queue depths, but what's interesting in DC P4500 is that it seems to use SLC cache that provides fast qd=1 4k random writes, close to 300MB/s (or ~90k IOPS), but qd=1 4k random reads are from totally different league (~38MB/s, ~10k IOPS). What is worse, it's not that difficult to exhaust that SLC cache and then your overall write performance drops BADLY. In my case, I was getting RBD write IOPS varying from 10 to 40k IOPS depending on if and for how long the write test was running and how heavy it was.
-- Piotr Dałek piotr.dalek@xxxxxxxxxxxx https://www.ovhcloud.com _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
