Re: Performance issues on Jewel 10.2.2

[Vincent Godin <vince.mlist@xxxxxxxxx>]

Hello,

I didn't look at your video but i already can tell you some tracks :

1 - there is a bug in 10.2.2 which make the client cache not working. The client cache works as it never recieved a flush so it will stay in writethrough mode. This bug is clear in 10.2.3

2 - 2 SSDs in JBOD and 12 x 4TB NL SAS in RAID0 are not very well optimized if your workload is based on write. You will perform in write at the max speed of your two SSD only. I don't know the real speed of your SSD nor your SAS disks but let's say:

your SSD can reach a 400 MB/s in write throughput

your SAS can reach a 130 MB/s in write throughput

i suppose that you use 1 SSD to host the journals of 6 SAS

Your max throughput in write will be 2 x 400 MB/s so 800 MB/s compare to the 12 x 130 MB/s = 1560 MB/s of your SAS

if you had 4 SSD for the journal, 1 SSD for 3 SAS

Your max throughput would be 4 x 400 MB/s so 1600 MB/s very near of the 1560 MB/s of your SAS

Of course, you need to adjust that with the real throughput of your SSD ans SAS disks

Vincent

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