Speed difference between 2 machines using Samba/ZFS

[serverguy]

OK, this is a complex issue. I am accessing a large ZFS share (16 TB RaidZ1) from multiple computers and a media play box.

First, a 64 bit desktop Win7 Pro machine with a 1Gb NIC. While loading the ZFS share, I was getting about 210 Mbs. That's not great. And frequent pauses between files. I thought it was ZFS overhead. I was unsure why it was so slow. It chugged along for almost a week to get everything loaded.

When I access the files, it takes a VERY long time get get a directory of about 250 folders on any of these machines. This happens on BOTH of my N4F boxes. 210 Mb/s should be adequate to get fast directories. And the drives are WD Green. Is that a problem? They should be fast enough, too. So no idea why the slowness.

Well, I experimented with FreeNAS to see if there was any speed increase. There was some but I would get horrible stutters watching movies. So back to N4F. Well, somehow, I managed to mangle the ZFS partition so I reset it and am reloading it through my laptop instead of the desktop.

The laptop has similar specs. 1GB/s NIC. But I am getting a true 500-600 Mb/s (65 MB/s) on the laptop. Same source box (Synology), same target N4F. But 3 times as fast. Huh???

So WHY is the directory listing so very slow. I am talking 30 to 40 seconds to list 250 folders. That's so trivial on every other box I have every used including the Synology source for this set of files.

I am quite amazed at how fast this laptop is at transferring data. Seems like it should be slower than a desktop machine. I am going through more switches and it is up to 3 times faster. To read the data, 2 switches. To write it, 2 of the same switches plus one more for a total of 3. And fast! Everything is Gb Ethernet here. Sometimes I feel like I don't know anything at all.

Confused in California!

[b0ssman]

go through this list.

http://n4f.siftusystems.com/index.php/2 ... /comments/

with the directory listing it sounds like you dont have zfs prefetch enabled.

[00Roush]

For slow directories try this... http://www.forums.nas4free.org/viewtopi ... =21&t=5401

Not sure what NAS4Free version you are using but here is what I previously posted for 9.1 and 9.2 versions...

I have found that these settings provide the best performance for NAS4Free with Windows 7:
If you are using ZFS install ZFS kernel tune and set to size of RAM.
Samba setup -- SMB2 (default), Send/Receive buffer size 0 (disables and lets the OS autotune), AIO enabled (default size of 4096), DOS attributes disabled (speeds up browsing folders with lots of files), and the rest at defaults.

I haven't tested the latest NAS4Free versions so I am unsure if the above is needed or not on 9.3.

00Roush