Will a Log / ZIL help me? - Low-Power Server

[kazjim]

First the specs:

HP N40L Microserver - AMD Turion(tm) II Neo N40L Dual-Core Processor
16GB RAM
3 x 4tb RAIDZ1
Separate Boot drive (5400 RPM)
1GB LAN

Version - FreeNAS-11.2-U3

I store a lot of Nikon RAW images to a share on FreeNas, and have a jail set up with NextCloud.
This all works pretty well, except the upload is nowhere near what I would have expected it to be.

I'm looking at the RaidZ1 array as being slow, and thinking a 120/250GB SSD is cheap enough to throw in as a write-cache / Log (ZIL)

Do you think I would see any real write performance improvements?

Where would I get the best improvements in write speeds?

Cheers

 

[KrisBee]

So what are your upload speeds in MB/s? On a 1Gb LAN ( it's bit not byte) the theoretical max xfer is 125MB/s, real world is likely to be around 100-115 MB/s, depending on various factors. As a comparison, what xfer speed do you get via a Windows share?

Suspect you are talking about using an SSD as a SLOG. Typical cheap consumer SSDs are no good for this use. A SLOG will only improve write performance in the case of "sync writes" ( see: https://www.ixsystems.com/community/threads/some-insights-into-slog-zil-with-zfs-on-freenas.13633/ and https://jrs-s.net/2019/05/02/zfs-sync-async-zil-slog/ and https://www.ixsystems.com/blog/o-slog-not-slog-best-configure-zfs-intent-log/ )

So is NextCloud generating a lot of "sync writes" on your pool? One way to tell is by monitoring the output of the zilstat command in the shell during uploads.

 

[SweetAndLow]

First the specs:

HP N40L Microserver - AMD Turion(tm) II Neo N40L Dual-Core Processor
16GB RAM
3 x 4tb RAIDZ1
Separate Boot drive (5400 RPM)
1GB LAN

Version - FreeNAS-11.2-U3

I store a lot of Nikon RAW images to a share on FreeNas, and have a jail set up with NextCloud.
This all works pretty well, except the upload is nowhere near what I would have expected it to be.

I'm looking at the RaidZ1 array as being slow, and thinking a 120/250GB SSD is cheap enough to throw in as a write-cache / Log (ZIL)

Do you think I would see any real write performance improvements?

Where would I get the best improvements in write speeds?

Cheers

Did you read the guide about slog devices? Go read it and you should see it won't help you

 

[Chris Moore]

Unless you are using a Mac... MacOS does ask for sync write if I recall correctly.

 

[kazjim]

Thanks all, I jsut couldnt understand the difference betweeb sync / async writes.

I assumed that a single file being uploaded from the NextCloud app or straight CIFS / SMB would be sync.

All good, thanks