[dm-crypt] Re : Poor performances with nfs and Kernel 3.x

Mickael mki2268 at yahoo.com
Wed Feb 8 16:04:57 CET 2012


>De : Arno Wagner <arno at wagner.name>
>À : dm-crypt at saout.de
>Cc : 
>Envoyé le : Mardi 7 février 2012 9h33
>Objet : Re: [dm-crypt] Poor performances with nfs and Kernel 3.x
>
>O.k., no such obervation with 3.2.2 on client and server. I got
>
>root /gate/tmp>cat ttt | wcs > /dev/null
>read:   2.147 GB [   2147483648 B]    avg:  69.274 MB/sec [    31 sec]
>
>(wcs, a.k.a. wc-stream is a small tool I wrote to do real-time
>monitoring of pipeline throughput and byte count, sources
>below.) This is with some ramp-up and almost 100% CPU load
>on the (slower) server. 
>
>I noticed though that nfsiostat is not the right tool to measure, as
>it gives you performance over the whole time the device has been 
>mounted, i.e. the throughput number keeps being updated in
>real-time. 
>
>Maybe re-run with wcs as shown above (compile instructions are in
>the header of wcs.c) and also monitor CPU usage on the server
>while this is rrunning, e.g. with "top". I am not saying you 
>imagine the issue, but lets be sure the measurement is good.
>
>If you do not want to compile anything, you could also use
>something like "time cat ttt > /dev/null" and calculate
>throughput manually. 
>
>Arno
>
>----- CUTed -----
>


Hello Arno,
Here are the new tests with wcs: results are still the same.

/tmp is the tmp directory on the client (7200 rpm HD)
/CRYPT is a crypted partition on the server (Green HD ~5600 rpm)
/SAV is a non-crypted partition on the server (Green HD ~5600 rpm)
CPU monitored with htop


*** Server with Kernel 3.0.0-15-server #26

* From client, using NFS on crypted partition:

cat /tmp/testfile.avi | wcs > /mnt/CRYPT/testfile.avi
 read:   2.032 GB [   2032330895 B]    avg:  41.476 MB/sec [    49 sec]

cat /mnt/CRYPT/testfile.avi | wcs > /tmp/testfile.avi
 read:   2.032 GB [   2032330895 B]    avg:  29.454 MB/sec [    69 sec]    <---------------

-----------

* From client, using NFS on non-crypted partition

cat /tmp/testfile.avi | wcs > /mnt/SAV/testfile.avi
 read:   2.032 GB [   2032330895 B]    avg:  72.583 MB/sec [    28 sec]

cat /mnt/SAV/testfile.avi | wcs > /tmp/testfile.avi
 read:   2.032 GB [   2032330895 B]    avg:  65.559 MB/sec [    31 sec]

-----------


* From Server:

cat /mnt/CRYPT/testfile.avi | wcs > /dev/null
 read:   2.032 GB [   2032330895 B]    avg:  72.583 MB/sec [    28 sec]

cat /mnt/SAV/testfile.avi | wcs > /dev/null
 read:   2.032 GB [   2032330895 B]    avg:  67.744 MB/sec [    30 sec]

-----------

cat /mnt/CRYPT/testfile.avi | wcs > /mnt/SAV/testfile.avi 
 read:   2.032 GB [   2032330895 B]    avg:  56.454 MB/sec [    36 sec]

cat /mnt/SAV/testfile.avi | wcs > /mnt/CRYPT/testfile.avi 
 read:   2.032 GB [   2032330895 B]    avg:  54.928 MB/sec [    37 sec]



===============================

*** Server with Kernel 2.6.38-13-server #52

* From client, using NFS on crypted partition:

cat /tmp/testfile.avi | wcs > /mnt/CRYPT/testfile.avi 
 read:   2.032 GB [   2032330895 B]    avg:  54.928 MB/sec [    37 sec]    CPU=100%

cat /mnt/CRYPT/testfile.avi | wcs > /tmp/testfile.avi 
 read:   2.032 GB [   2032330895 B]    avg:  81.293 MB/sec [    25 sec]    CPU=98%        <-------------------

-----------

* From client, using NFS on non-crypted partition

cat /tmp/testfile.avi | wcs > /mnt/SAV/testfile.avi
 read:   2.032 GB [   2032330895 B]    avg:  63.510 MB/sec [    32 sec]    CPU=50%

cat /mnt/SAV/testfile.avi | wcs > /tmp/testfile.avi
 read:   2.032 GB [   2032330895 B]    avg:  63.510 MB/sec [    32 sec]    CPU=25%



* From Server:

cat /mnt/CRYPT/testfile.avi | wcs > /dev/null
 read:   2.032 GB [   2032330895 B]    avg:  84.680 MB/sec [    24 sec]    CPU=98%

cat /mnt/SAV/testfile.avi | wcs > /dev/null
 read:   2.032 GB [   2032330895 B]    avg:  67.744 MB/sec [    30 sec]    CPU=25%

-----------

cat /mnt/CRYPT/testfile.avi | wcs > /mnt/SAV/testfile.avi 
 read:   2.032 GB [   2032330895 B]    avg:  52.111 MB/sec [    39 sec]    CPU=50%-100%

cat /mnt/SAV/testfile.avi | wcs > /mnt/CRYPT/testfile.avi 
 read:   2.032 GB [   2032330895 B]    avg:  47.264 MB/sec [    43 sec]    CPU=75%-100%


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