Poor performance on SSD's

[cpro93]

Hello Everyone!

I am new to the Starwind virtual SAN. I have it set up on a server running Windows Server 2012 data center and then I have one NIC going to my ESXi host. I have two Image files, one is on a RAID 10 of four 7200RPM hard disk drives, and the other is on a RAID 0 of two Samsung SSD's. I noticed that my performance on my ESXi host between the two image files is very different, the data store set up on the SSD image file is much slower than the data store set up on the HDD image file. On the host server itself, I can write to the SSD disk at over 300MB/s, but my ESXi host seems to be getting around 10MB/s to the image file stored on the same disk. I am not sure where my bottleneck is because I am getting good performance on the other image file on the HDD's, so I don't think it is a networking issue, and since I get really fast speeds on the Windows host, I don't think it is a RAID problem. I have both image files set up with 1GB of L1 cache and I do not have L2 cache set up. Any insight as to where else I can look or how I can increase these speeds would be very helpful. Thank you.

[darklight]

Try disabling L1 cache for SSD's and test once again

[cpro93]

I tried that and it didn't help Still getting only about 10-12MB/s read/write speeds.

[darklight]

It's rather hard to say what could be the problem since there are a lot of factors which could bottleneck your performance. I would recommend you to benchmark your system according to this guide: https://www.starwindsoftware.com/starwi ... ice-manual. You can also use IOMeter guide found here: https://knowledgebase.starwindsoftware. ... -of-tests/. Step-by-step benchmarking will allow you to determine on which step occurs performance loss and find the bottleneck.

[cpro93]

So I ran tests using ATTO Disk Benchmark on a VM on my ESXi Host and on the local disks on the server hosting the StarWind Virtual SAN software. I disabled all cache and the only VM running was the one that was running the tests (a brand new server 2012 r2 install, nothing else on it). I have one NIC between the server and the ESXi host. I ran three tests on a VM on the ESXi host, one on a RAM disk (called RAM Disk Performance over iSCSI), one on the device image stored on HDD's in a RAID10 (called HDD Performance over iSCSI), and one on SSD's in a RAID0 (called SSD Performance over iSCSI). I also ran two tests on the local server hosting the StarWind virtual SAN software, on the same set of HDD's and SSD's (I shut down the VM and stopped the StarWind service to make sure there was no other disk IO). The test screen shot on the HDD's is called (HDD Local Performance) and the test on the SSD's called (SSD Local Performance). Thank you for all the help! (Sorry for having to zip up the screen shots)

[Delo123]

Are the Ramdisk screenshots missing?
Also your local ssd results seem "low", are these new emtpy ssd's? how are they connected? (Controller)

[Oles (staff)]

Hello!

Please let me know if any further assistance is required here, thank you.

[Trevbot]

Take a look at my thread here: https://forums.starwindsoftware.com/vie ... f=5&t=4067 I had similar issues with SSD backed thick disks on an LSI controller in v8. I was not running raid and running in both IR and IT modes gave very poor performance on SSD. Taking the LSI controller out and connecting the SSDs directly to the MB showed a return to expected SSD performance. I will also note that while the SSDs connected to the LSI controller performed very poorly in v8, the same configuration runs like a champ on v6. LSFS performance with this config in v8 was good but LSFS had several other issues at the time and I didn't need it for my application anyway. You may want to try directly connecting your SSD(s) to your MB and see if performance improves.

[darklight]

Sometimes specific settings of HW Raid controller also may increase\decrease performance. Stripe size, cache size and possibly other settings, especially for SSDs.

[Tarass (Staff)]

Do you need any further assistance here?