> À : dm-crypt@xxxxxxxx > Cc : > Envoyé le : Mardi 7 février 2012 9h11 > Objet : Re: Poor performances with nfs and Kernel 3.x > > On Mon, Feb 06, 2012 at 10:28:24PM +0000, Mickael wrote: >> Hello, >> >> I'm writing about poor performances accessing a dm-crypt/LUKS partition >> using nfs. >> >> I was running a fileserver Ubuntu_Server_11.04 (Kernel 2.6.38-13#52) with >> no problem. But after an upgrade to Ubuntu_Server_11.10 (Kernel >> 3.0.0-15#26) reading and writing a crypted partition with nfs is very >> slow. > >Interesting. I think have no issues here with Debian stable and Kernel >3.2.2 on the server and 3.1.6 on the client. > >What is the kernel version on your client? My client is an Unbutu 3.0.0-15#26 amd64 (2 CPU) Results are the same, using a 2.6 or 3.0 Kernel on the client. The problem seems to be located on the server only >3.0.0 is not a very good kernel though with a number of issues. >There is also a local privilege excalation in 3.x that has been >fixed only in 3.2.2 and later. (Unless Ubuntu did it.) I've build a Fedora 16 (3.2.1-3) with no change I need to find a distro with a recent Kernel (>3.2.2) to test if it solve the problem > >> >> I've made different tests with a 2GB file to show the difference when the >> server is running a 2.6 or 3.0 kernel. All others parameters are always >> the same. >> >> First, a test using nfs to access a crypted partition (dm-crypt/LUKS/ext4) >> on the server: >> >> *Svr Kernel 3.0.0-15#26? : NFS (R/W) = 30 MB/s / 33 MB/s?? <-------- The problem is here ! >> *Svr Kernel 2.6.38-13#52 : NFS (R/W) = 81 MB/s / 53 MB/s >> >> As you can see, with the Kernel 3.0, performances are very bad. The flow >> is always constant at ~30MB; there's clearly a limitation > >What did you use to do the benchmark? Just coying a 2GB avi file with time cp /tmp/testfile.avi /mnt/CRYPT/ and calculate the average speed (2000MB/time_sec) > >> For comparison, the same test, but this time, using nfs to read and write >> a non-crypted partition (ext4) (same HD of the crypted partition): >> >> *Svr Kernel 3.0.0-15#26? : NFS (R/W) = 92 MB/s / 77 MB/s >> *Svr Kernel 2.6.38-13#52 : NFS (R/W) = 111 MB/s / 74 MB/s >> Using nfs without dm_crypt, performances are good with the 2 Kernels > >Interesting. > >I will do a benchmark here and see whether I have the same. > >Arno > >------ Cut ------ > >-- >Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: arno@xxxxxxxxxxx >GnuPG: ID: 1E25338F FP: 0C30 5782 9D93 F785 E79C 0296 797F 6B50 1E25 338F >---- >One of the painful things about our time is that those who feel certainty >are stupid, and those with any imagination and understanding are filled >with doubt and indecision. -- Bertrand Russell >_______________________________________________ >dm-crypt mailing list >dm-crypt@xxxxxxxx >http://www.saout.de/mailman/listinfo/dm-crypt De : Arno Wagner <arno@xxxxxxxxxxx> _______________________________________________ dm-crypt mailing list dm-crypt@xxxxxxxx http://www.saout.de/mailman/listinfo/dm-crypt
