Slow writes HP P420

azanotti

New Member
Aug 27, 2019
8
0
1
Hi,
i have recently acquired a new DL360e with a P420 raid controller. I have installed one 120gb ssd (consumer) and set up RAID 0. When i booted into the os (Vmware) and created a vm i noticed that it was running very slowly and the disk speed test (CrystalDiskMark) reported read speeds of 340MB/s and write speeds of 54 MB/s. The average reading for that disk should be 540 MB/s and the writes should be around 490 MB/s. I have also tried changing the card mode to HBA but i couldn't create a datastore with vmware due to a driver issue. I have then booted into a USB linux and doing a disk speed test reported almost the same writes and reads of before. I have tried changing the cache ratio to 75/25 (before it was 100/0) but it made things worse.
What could i do?
Thaks
 

tomaash

Active Member
Oct 11, 2016
103
48
28
Europe, Slovakia
P420 does sync writes to the SSD and this is something consumer SSDs tend not to be good at.
You could disable SSD SmartPath, make sure that controller cache is enabled on the volume, set controller caching to 10/90 read/write, and after some thought enable drive write cache.
You should replace the consumer SSD with enterprise-grade/powerloss protected one, which provides more consistent performance using more extensive overprovisioning, better NAND and more channels to the NAND, not to speak of powerloss protection for it's volatile cache that allows enterprise-grade SSDs to confirm writes as soon as they hits the buffer.
Also you should not use Raid5/6 even with SSDs, if you expect decent performance.
 

azanotti

New Member
Aug 27, 2019
8
0
1
P420 does sync writes to the SSD and this is something consumer SSDs tend not to be good at.
You could disable SSD SmartPath, make sure that controller cache is enabled on the volume, set controller caching to 10/90 read/write, and after some thought enable drive write cache.
You should replace the consumer SSD with enterprise-grade/powerloss protected one, which provides more consistent performance using more extensive overprovisioning, better NAND and more channels to the NAND, not to speak of powerloss protection for it's volatile cache that allows enterprise-grade SSDs to confirm writes as soon as they hits the buffer.
Also you should not use Raid5/6 even with SSDs, if you expect decent performance.
Thank you very much, i have followed all of your steps and there was an improvent but still not was i was looking for. I then decided to throw away VMware and installed Windows Server 2016 directly and the speeds were awesome with your configuration.