Pogoplug v4 I/O performance issues, how to tweak?

[tilllt]

Does anyone know if there is work being done on making exFat support more efficient in Linux?
I read there is proprietary, higher performance driver by Paragon, so i guess there must be some room for improvement...

[moonman]

Samsung released GPLed exfat driver, but we cannot use it because we still need a license from M$ to use the code. You, however can use it on your own: https://gitorious.org/binbang/exfat-lin ... 6fad82621a:
And there's a package in AUR: https://aur.archlinux.org/packages/exfat-dkms-git/

[tilllt]

Cool, thanks for the hint.
I think beyond the problem of ExFat there must be something wrong with my configuration, i don't even get close to the data rates mentioned by this guy:

http://fortysomethinggeek.blogspot.dk/2 ... eview.html

The fastest i can get is copying from ext3 to ext3 but that maxes out at around 30mb/s...
maybe somebody can repeat a drive to drive copy speed test and tell me if i should look further or if thats the max i can get. The guy from the blog mainly did iperf and dd copy tests (on single drives) so i guess the performance between two drives could be very different. maybe somebody can confirm that?

in "theory" everything looks great", in practice, when accessing a SMB share, copy data from one disk to another, things get really slow, sometimes even though the PPv4 is neither at 100%cpu nor memory...

iperf -c 192.168.1.246 -d
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 128 KByte (default)
------------------------------------------------------------
------------------------------------------------------------
Client connecting to 192.168.1.246, TCP port 5001
TCP window size: 129 KByte (default)
------------------------------------------------------------
[ 5] local 192.168.1.11 port 64305 connected with 192.168.1.246 port 5001
[ 6] local 192.168.1.11 port 5001 connected with 192.168.1.246 port 39089
[ ID] Interval Transfer Bandwidth
[ 5] 0.0-10.0 sec 97.8 MBytes 81.9 Mbits/sec
[ 6] 0.0-10.0 sec 101 MBytes 84.5 Mbits/sec

[swass]

http://linuxengineering.wordpress.com

[moonman]

Great work. I might use a couple of your tweaks

A couple of things I found: noatime already implies nodiratime
deadline performed better on a spinning disk? last time I checked (2 years ago?) bfq gave a good performance boost over cfq and deadline. I might re-bench it again.

EDIT: On GoFlex Home with samba around 65 down and 35 up. Though I did modify the config a bit because yours was giving me disconnects all the time: socket options add SO_KEEPALIVE and removed these
$this->bbcode_second_pass_code('', '# max xmit = 65535
# max connections = 8
# deadtime = 15
')

That is default max xmit anyway.

Good stuff

[swass]

Thank you.

I added some additional notes based on your experience to the guide. Based on what I can find, your Seagate GoFlex has the 1200MHz processor which explains the better throughput. It also has more memory. I'm jealous.

Good point on the nodiratime -- I threw it in there as implied, but it isn't necessary. The same was true of the max xmit, just to imply that if it was set differently, one might consider changing it.

Typically you'll see deadline used with enterprise server applications, such as Oracle RDBMS when using block storage. Although it doesn't imply that under all cases deadline will be better -- people should always test based on what they use their systems for. Benchmark tools are great, but they are synthetic and don't represent all real-world uses.

[WarheadsSE]

Nicely done. This should, in theory, be applicable for most of the Kirkwoods. I will have to re-visit my NSA325 (1.6Ghz w/ 512M, 2x SATA) And see how that memory and CPU impacts it.

[swass]

It would be interesting to see your results and whether or not buffered i/o has the same negative impact on i/o performance as with the slower Pogoplug v4. If I can find one cheap enough, I might look into getting one of those devices like yours.

[WarheadsSE]

Here is the NSA325v2 which is as far as I understand it is pin-compatible with the NSA325, thus logically identical inside Linux http://www.amazon.com/High-Performance- ... B00GJYNLKM

Here is the NSA320 which is the "younger" brother, 1.2Ghz, 512M, 2x SATA http://www.amazon.com/NSA320-Performanc ... B004UBU3SY

You might be able to find either of these on eBay or the ilk for less.

[grayman4hire]

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