Cache strategy needed by turning off write cache on harddisk device

FAQ, getting help, user experience about PrimoCache
Post Reply
Cybermage
Level 1
Level 1
Posts: 4
Joined: Fri May 04, 2018 7:00 pm

Cache strategy needed by turning off write cache on harddisk device

Post by Cybermage »

Screenshot_1.png
Screenshot_1.png (97.06 KiB) Viewed 2642 times
I have the following configuration 2x 10 TB x300 toshiba harddisk's 1 x 2 TB 970 evo SSD.
L1 cache of 16 GB and and L2 cache of 1.42 TB and it works very good.
I have Cache hit rates of 98% when using starting virtual machines. :D

as inspiration of the following topic
https://www.romexsoftware.com/bbs2/en-u ... =33&t=4667

Screenshot_3.png
Screenshot_3.png (14.03 KiB) Viewed 2642 times
i start experimenting to turn off the write cache on of my Toshiba 10 TB harddisk
then i copy a directory with files of the size in total of 280 GB the speed drops from 200 MB/s to 70 MB/s per second.
the directory contains files of diffent file sizes.
if there a way to of better handeling the write cache by primocache?
Please some advise on this matter.
User avatar
Jaga
Contributor
Contributor
Posts: 692
Joined: Sat Jan 25, 2014 1:11 am

Re: Cache strategy needed by turning off write cache on harddisk device

Post by Jaga »

I've been told by Romex support in the past to simply leave the Windows write-caching algorithm at it's default setting. Enable write caching in that interface, but leave write-cache buffer flushing off.
Cybermage
Level 1
Level 1
Posts: 4
Joined: Fri May 04, 2018 7:00 pm

Re: Cache strategy needed by turning off write cache on harddisk device

Post by Cybermage »

Did some more experimenting and when i turn off write cache and turn on Defer write i got the same speed 200 MB/s. Only in the beginning the speed is higher think it is the burst.
User avatar
Support
Support Team
Support Team
Posts: 3623
Joined: Sun Dec 21, 2008 2:42 am

Re: Cache strategy needed by turning off write cache on harddisk device

Post by Support »

Windows write caching is happened on file system level which is handled first before PrimoCache disk level. When you turn off Windows write caching, file system will directly deliver write-data to disk, this takes some process time and causes speed down.
Post Reply