Bug #4352
librbd: increased memory usage on bobtail vs argonaut (and with no caching)
0%
Description
On irc, t0rn reports increased memory usage with caching turned off, and with bobtail compared to argonaut:
(09:40:26 AM) t0rn: joshd1: that is correct, with rbd cache set to true (other settings default) i see less memory usage of the qemu process. For the test I just start a VM, with this loop: 'while true; do dd if=/dev/zero of=/dev/vdb bs=1M ; done' and watch the memory usage climb. Doing that I see more usage when caching is off (09:41:11 AM) t0rn: where vdb is the rbd volume (09:45:25 AM) t0rn: so far i've only ran the test for 24 hours each, and it does appear to flat line somewhat (http://tinypic.com/view.php?pic=2q3dkav&s=6) thats a graph showing the results of the above test, but with rbd cache disabled (argonaut vs bobtail) (09:47:29 AM) t0rn: i'm not sure what memory overhead i should expect under normal circumstances from qemu-rbd setups over the instance allocated amounts. That graph was from a vm granted 512mb through qemu (09:48:43 AM) joshd1: t0rn: those are with the same size cluster with images in the same pool? (09:49:00 AM) t0rn: same cluster and pool yes. The only difference was the client librdb versions (09:51:16 AM) t0rn: centos 6.2 , compiled from source: 1.) qemu 1.1.2 2.) librbd from v0.56.3 (6eb7e15a4783b122e9b0c85ea9ba064145958aa5) 3.) libiscsi 1.5.0 4.) libvirt 1.0.1 (09:58:45 AM) t0rn: i built with gperftools-devel,gperftools-libs 2.0-3.el6.2 from http://code.google.com/p/gperftools i used nss-devel-3.12.10-17.el6_2 (stock centos package)
The attached graph shows bobtail vs argonaut with caching off.
Associated revisions
common: reduce default in-memory logs for non-daemons
The default of 100000 can result in hundreds of MBs of extra memory
used. This was most obvious when using librbd with caching enabled,
since there was a dout(0) accidentally left in the ObjectCacher.
refs: #4352
backport: bobtail
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
common: reduce default in-memory logs for non-daemons
The default of 100000 can result in hundreds of MBs of extra memory
used. This was most obvious when using librbd with caching enabled,
since there was a dout(0) accidentally left in the ObjectCacher.
refs: #4352
backport: bobtail
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
(cherry picked from commit 7c208d2f8e3f28f4055a4ae51eceae892dcef1dc)
History
#1 Updated by Sage Weil about 11 years ago
- Assignee set to Josh Durgin
just merged the fix for this into next. still needs to be cherry-picked to bobtail branch.
#3 Updated by Josh Durgin about 11 years ago
- Status changed from 7 to Resolved