How to increase memory size of the write cache?

[kiteboarder]

Hi friends,

Does anyone know how to set/increase the memory size of the disk write cache? I've attached a picture showing that Server 2016 R2 limits it to 64 GB on my 128 GB machine. Windows 10 pro limits this to a much smaller value. It's definitely not 50% of RAM.

I've tried google and the power shell online guides - no luck. Any help would be greatly appreciated!

Thanks in advance!

 

[cesmith9999]

You can change the write cache on a Storage Space Volume on setup (no luck after you put data on it) of the volume. but there is no way to change the write cache values in the memory cache.

If you want a smoother write out to disk. look up some of my previous posts with registry key settings. Those should help a bit.

Chris

 

[kiteboarder]

Very much appreciate your reply, even though the news isn't very good. ;-)

Any idea why the size of the memory write cache in Windows 10 is a much smaller value than Server?

Sorry that I'm a bit of a noob when it comes to searching this forum. I wasn't easily able to find your previous posts with registry settings, but I will keep looking.

Thanks again!

 

[cesmith9999]

Any idea why the size of the memory write cache in Windows 10 is a much smaller value than Server?

Yes I know why. The same reason that windows (client) is limited to 10 SMB connections. Product differentiation.

https://forums.servethehome.com/index.php?threads/super-low-10g-performance.8394/page-2#post-76577

Chris

 

[Stefan75]

My file server is on W10 pro and has 24GB RAM.
When I copy to using 10gbit nics I get about 400MB/s for about 3GB, then it drops to disk speed (about 100MB/s).
So I'd have to get more RAM or change to Windows Server to get more caching?

 

[Evan]

Are you sure it’s not your SSD cache full, sounds about how big a lot of SLC cache is on consumer TLC SSD’s

 

[kiteboarder]

After a few months of extensive testing, I have verified what I originally wrote. Windows Server allows about 50% of RAM for write cache, but Windows 10 only allows about 10% of RAM for write cache. This is very easy to verify in a single machine coping a large file from a fast M.2 SSD to a spinning disk. You'll see exactly what Stefan75 wrote above.

cesmith9999 gave the best solution - you basically have to build a new storage space with sufficient SSDs (or many HDDs) for the desired level of write cache performance.

I've basically decided that unless you want to play games or need HDR, then it's better to just use Windows Server.

(Or if you've got free pci-e lanes, the new WD black M.2 SSDs can do better than 2,000 MB/s writes. Samsung 970s are similar.)

 

[kiteboarder]

See attached for an example of the memory write cache filling up. This is "normal" behavior for writing to a HDD with ~220 MB/s write speed.

 

[Stefan75]

After a few months of extensive testing, I have verified what I originally wrote. Windows Server allows about 50% of RAM for write cache, but Windows 10 only allows about 10% of RAM for write cache. This is very easy to verify in a single machine coping a large file from a fast M.2 SSD to a spinning disk. You'll see exactly what Stefan75 wrote above.

I switched my server (24GB RAM) from W10 to 2016.
Now SMB copy slows down after 8GB of data.