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NAS Copy to Freenas VM - incredibly slow - but other operations very good

dannyboy1121

Newbie
Joined
Oct 28, 2019
Messages
3
Hi,

Just posting this up in case it's an obvious known issue as I've found a work around for now. It's more for my understanding than anything else.

I'm running a Freenas VM on vSphere 6. Freenas is at 9.10.1-u2 and is a very simple non-production deployment with 2 cores, 12 GB RAM, 1 x SATA HDD and an SSD installed locally to the ESXi node. I've created a ZFS pool with the HDD and SSD as L2 ARC - no ZIL.

What I've noticed is that SMB / NFS copy operations to shares on the Freenas box can be incredibly slow. After 400 MB of data, the copy rate drops through the floor to bytes. CPU usage is low at this point. A recent example, trying to copy an iphoto archive from a mac across to the Freenas box via SMB resulted in it grinding to a halt, the archive comprising mainly of thousands of fairly small image a metadata files.

On the destination dataset, sync = disabled.

This is what confuses me - my work around was to run an SCP job to recursively copy out the iphoto archive across to the backup directory on the NAS - at which point I get up to 50 MB per second throughput. For a VM with two disks, that's about as much as I'd expect and I'm really happy with it.

So the VM and associate hardware is capable, but there seems to be a significant issue when using NAS protocols yet with SCP having no problems whatsoever. This is obviously a config issue where I've missed best practice or similar, but I'm wondering where other people with better experience of Freenas would start to troubleshoot (accepting that these could even be client issues).

Any thoughts appreciated.
 

Jessep

Senior Member
Joined
Aug 19, 2018
Messages
292
Why would you run an OS/FS that's only purpose is to protect your data in such a manner as to prevent that protection?
 

dannyboy1121

Newbie
Joined
Oct 28, 2019
Messages
3
Why would you run an OS/FS that's only purpose is to protect your data in such a manner as to prevent that protection?
The integrity of that particular dataset is unimportant during the copy phase. It's a backup The dataset subsequently gets replicated elsewhere so I have two copies at any one time. I've really posted here to source experience on poor NAS performance (SMB in particular), so any help there would be appreciated.
 

HoneyBadger

Mushroom! Mushroom!
Joined
Feb 6, 2014
Messages
2,661
Ah, it's a Mac. You need to disable SMB strict sync.

In the SMB auxiliary settings (Services -> SMB -> Little Wrench Icon) set strict sync = no; you may need to restart the service to see the effects.
 

dannyboy1121

Newbie
Joined
Oct 28, 2019
Messages
3
Ah, it's a Mac. You need to disable SMB strict sync.

In the SMB auxiliary settings (Services -> SMB -> Little Wrench Icon) set strict sync = no; you may need to restart the service to see the effects.
Cheers - really appreciated. Will test this and report back.
 
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