|Summary:||[Bug 4689] slow network transfer using tar to remote host|
|Product:||[Retired] Red Hat Linux||Reporter:||Robert K. Moniot <moniot>|
|Component:||tar||Assignee:||Bernhard Rosenkraenzer <bero>|
|Status:||CLOSED NOTABUG||QA Contact:|
|Fixed In Version:||Doc Type:||Bug Fix|
|Doc Text:||Story Points:||---|
|Last Closed:||2000-05-05 17:34:21 UTC||Type:||---|
|oVirt Team:||---||RHEL 7.3 requirements from Atomic Host:|
|Cloudforms Team:||---||Target Upstream Version:|
Description Robert K. Moniot 2000-01-20 14:24:24 UTC
On 01/13/00 22:44 email@example.com wrote: > +we never were able to duplicate this. If you are still having problems, > or the > +problem was not solved in 6.1, please reopen the bug. I want to reopen this bug. It has not gone away with 6.1. I found a way to demo this problem without need of a tape drive. We have two systems here, named pascal and sobolev. Both are Compaq Deskpros with CPU >= 300 MHz, running RedHat 6.1. They are connected via Netelligent 10/100 TX (tlan) network interfaces, to a LAN via CAT5 UTP (10base-T), so neither cpu nor network bandwidth are problems. They share account information via NIS. Procedure: Given filesystems: 1) /u/pascal that is local to pascal and NFS mounted by sobolev. A suitably large subdirectory foo (25 MB) is located in this filesystem, and is to be backed up onto a file on sobolev. 2) /tmp is local to sobolev, and is to receive the backup file. The procedures below are executed as a normal user with an account on both hosts, and permission to run r-commands on sobolev (e.g. via the .rhosts mechanism). Slow method: Logged in on host pascal, chdir to local filesystem /u/pascal. pascal:/u/pascal/$ time tar cf sobolev:/tmp/remote.tar foo 0.750u 2.350s 1:11.49 4.3% 0+0k 0+0io 7433pf+0w Fast method: On host sobolev, chdir to the NFS filesystem pascal:/u/pascal. sobolev:/u/pascal/$ time tar cf /tmp/nfs.tar foo 0.320u 2.990s 0:37.12 8.9% 0+0k 0+0io 187pf+0w sobolev:/u/pascal/$ ls -l /tmp/*.tar -rw-r--r-- 1 moniot staff 25937920 Jan 14 12:17 /tmp/nfs.tar --w---xr-- 1 moniot staff 25937920 Jan 14 12:15 /tmp/remote.tar* Do the math: Slow method: 26 MB/ 71 s = 370 KB/s Fast method: 26 MB/ 37 s = 700 KB/s The numbers vary a bit depending on system and network load, but the basic difference remains. With the tape drive we are seeing a bigger difference (a factor of 3 to 4), but that seems to be due to the tape drive being on an alpha-OSF system. (The permissions of remote.tar look a bit odd too, now that I notice them. But never mind that now.) -- Bob Moniot Fordham University email: firstname.lastname@example.org Fordham College Lincoln Center URL: http://www.dsm.fordham.edu/~moniot/ New York, NY 10023 phone: (212) 636-6311
Comment 1 Preston Brown 2000-02-11 16:46:59 UTC
jeff or bero: do you have time to investigate this?
Comment 2 Bernhard Rosenkraenzer 2000-02-11 17:29:59 UTC
Not today (config tool freeze) - maybe later.
Comment 3 Preston Brown 2000-05-05 17:34:59 UTC
Bero: please investigate.
Comment 4 Bernhard Rosenkraenzer 2000-08-08 16:23:51 UTC
This is normal NFS overhead in the way tar works (opening a series of small files over nfs has a lot of overhead); can't be fixed.