I have made some tests with the WD Ultrastar DC SS 530 as WD promoted it as the fastest SSD. They are 12G dualpath SAS and available with a different 4k random write performance between 100k and 320k write iops and with capacities between 400GB (perfect for an Slog) and 15 TB for regular storage.
In my first test I want to use it mainly as an Slog in a dualpath HA SAS setup as this is where I cannot use an Optane. First results
A disk pool from 3 disks in Raid-0 without Slog
Async write: > 800 MB/s
Sync Write: 50 MB/s (bad, but normal for disks)
Same pool with an Slog DC SS 530 400 GB (3DW model)
sync write: 400 MB/s (a huge jump from 50 MB/s)
Then I compared a single disk pool from the SS 530 with an Optane 900P.
As this test was for a vCluster in a box, the SS 530 was in passthrough mode under ESXi and the P900
on a barebone setup from former tests so values are not exact but give enough insights.
DC SS 530 (single disk pool), AiO
Async write: 1007 MB/s
Sync Write: 550 MB/s
Optane 900, barebone
Async Write: 1611 MB/s
Sync Write: 680 MB/s
The SS 530 is only 20% slower in this test on sync write.
Perfect result as this is dualpath SAS and suited for HA.
And perfect for a high capacity/ high performance filer.
datasheet
https://documents.westerndigital.co...-sas-series/data-sheet-ultrastar-dc-ss530.pdf
see chapter 7.2
http://www.napp-it.org/doc/downloads/z-raid.pdf
In my first test I want to use it mainly as an Slog in a dualpath HA SAS setup as this is where I cannot use an Optane. First results
A disk pool from 3 disks in Raid-0 without Slog
Async write: > 800 MB/s
Sync Write: 50 MB/s (bad, but normal for disks)
Same pool with an Slog DC SS 530 400 GB (3DW model)
sync write: 400 MB/s (a huge jump from 50 MB/s)
Then I compared a single disk pool from the SS 530 with an Optane 900P.
As this test was for a vCluster in a box, the SS 530 was in passthrough mode under ESXi and the P900
on a barebone setup from former tests so values are not exact but give enough insights.
DC SS 530 (single disk pool), AiO
Async write: 1007 MB/s
Sync Write: 550 MB/s
Optane 900, barebone
Async Write: 1611 MB/s
Sync Write: 680 MB/s
The SS 530 is only 20% slower in this test on sync write.
Perfect result as this is dualpath SAS and suited for HA.
And perfect for a high capacity/ high performance filer.
datasheet
https://documents.westerndigital.co...-sas-series/data-sheet-ultrastar-dc-ss530.pdf
see chapter 7.2
http://www.napp-it.org/doc/downloads/z-raid.pdf