Hi all, now that prices on entry-level enterprise SSDs are dropping thanks to TLC-NAND, I thought it would be a good time to revisit SSDs in servers for lower end clients. However, in testing configurations, I am having very significant performance issues, significant enough that it felt much slower than HDD based RAID 10 configurations that were otherwise configured identically.
I have a feeling that this has to do with the RAID controllers caching policies, however, I have not yet managed to get close to typical HDD-in-RAID 10 speeds, let alone where SSDs should be.
My current configuration is 4 Samsung 883 DCT 960GB SSDs configured in RAID 10 with the Dell H710p controller. "No read ahead" and "Write Through" cache policies are applied in the controller. Disk cache is disabled in the controller. Disk cache is enabled in the Virtual Disk Management in Windows, as it is the default, however, I do not know if this actually controls anything, as the drive is in a RAID configuration and not directly managed by Windows. Windows Server 2016. HyperV and VMs.
AS-SSD benchmark (I know not the best, any recommendations are more than welcome), shows that seq. read speeds are at 297MB/s as opposed to the HDD config at 812MB/s, seq. write speeds are at 90MB/s versus 388MB/s for the HDD setup. 4K writes are at 7MB/s vs. 23MB/s for the HDD Setup. 4K reads are at .77MB/s vs 1.61MB/s for the HDDs. And so on with ridiculously low performance numbers.
I was not able to find a clear consensus on what the settings should be to extract the performance out of the SSDs. I've tried different combinations, but some were even worse than these numbers. Any help would be very much appreciated!
I have a feeling that this has to do with the RAID controllers caching policies, however, I have not yet managed to get close to typical HDD-in-RAID 10 speeds, let alone where SSDs should be.
My current configuration is 4 Samsung 883 DCT 960GB SSDs configured in RAID 10 with the Dell H710p controller. "No read ahead" and "Write Through" cache policies are applied in the controller. Disk cache is disabled in the controller. Disk cache is enabled in the Virtual Disk Management in Windows, as it is the default, however, I do not know if this actually controls anything, as the drive is in a RAID configuration and not directly managed by Windows. Windows Server 2016. HyperV and VMs.
AS-SSD benchmark (I know not the best, any recommendations are more than welcome), shows that seq. read speeds are at 297MB/s as opposed to the HDD config at 812MB/s, seq. write speeds are at 90MB/s versus 388MB/s for the HDD setup. 4K writes are at 7MB/s vs. 23MB/s for the HDD Setup. 4K reads are at .77MB/s vs 1.61MB/s for the HDDs. And so on with ridiculously low performance numbers.
I was not able to find a clear consensus on what the settings should be to extract the performance out of the SSDs. I've tried different combinations, but some were even worse than these numbers. Any help would be very much appreciated!
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