[Lustre-discuss] Using SSDs for OSS Read Cache on servers with little RAM?
Any possibility to redirect Lustre's OSS Cache or portions of the Linux pagecache to a location other than RAM such as to an internal SSD (perhaps even two in RAID0). I ask because the servers we have available (read: second hand servers) for OSSs physically max out at 8GB RAM. The wiki states: *"It uses a regular Linux pagecache to store the data."* I looked into pagecache and pdflush tunables but found little on directing the actual location of the cached content as it tends to focus heavily on tuning timing of writes-*to*-disk vs reads.Yes, I understand the absurdity of trying to redirect RAM cached content back to "disk" but with rapidly evolving SSD design and performance it actually makes some sense in this case for Lustre cache data. Obviously I would prefer to redirect *only*Lustre OSS cache data and not the entire Operating System page cache. While an SSD is nowhere near as quick as RAM, it would still seem beneficial to have more frequently viewed content available for reads even from an SSD vs a spinning disk, especially with our use case (HD video editing and playback). Until SSD prices come down to reasonable levels and we can afford to replace all spinning disks with SSDs, any little bit helps ;-) In sum: just a thought to be able to designate, in Lustre configs, an additional low-latency "swap" or "cache" location on the OSSs. Adding one SSD to each OSS sure beats having to buy new servers with more RAM capacity or using all SSD drives and blowing the budget... Thanks for the time, Scott Adametz Systems Engineer Big Ten Network FOX Networks Group scott.adam...@fox.com ___ Lustre-discuss mailing list Lustre-discuss@lists.lustre.org http://lists.lustre.org/mailman/listinfo/lustre-discuss
Re: [Lustre-discuss] MDS crashes daily at the same hour
Brian J. Murrell wrote: > On Wed, 2010-01-06 at 11:25 +0200, David Cohen wrote: >> I was indeed the *locate update, a simple edit of /etc/updatedb.conf on the >> clients and the system is stable again. > I've just encountered the same thing - the mds crashing at the same time several times this week. It's just after the *locate update - I've added lustre to the excluded filesystems, and so far so good. > Great. But as Andreas said previously, load should not have caused the > LBUG that you got. Could you open a bug on our bugzilla about that? > Please attach to that bug an excerpt from the tech-mds log that covers a > window of time of 12h hours prior to the the LBUG and an hour after. > I don't see an LBUG in my logs, but there are several Call Traces. Would it be useful if I filed a bug too or I could add to David's bug if you'd prefer - if so, can you let me know the bug number as I can't find it in bugzilla. Would you like /tmp/lustre-log.* too? Chris ___ Lustre-discuss mailing list Lustre-discuss@lists.lustre.org http://lists.lustre.org/mailman/listinfo/lustre-discuss
[Lustre-discuss] ll_inode_revalidate_fini()) failure -108 inode
Hello, Using 1.8.1.1 server/patched client, with one OST for now, remote directory mounted with "flock" option. I the following appears in kernel log: LustreError: 12864:0:(mdc_locks.c:618:mdc_enqueue()) ldlm_cli_enqueue: -108 LustreError: 12864:0:(mdc_locks.c:618:mdc_enqueue()) Skipped 2103 previous similar messages LustreError: 12881:0:(file.c:3143:ll_inode_revalidate_fini()) failure -108 inode 1024203 LustreError: 12881:0:(file.c:3143:ll_inode_revalidate_fini()) Skipped 2103 previous similar messages With the same inode number each time. Actually, this appears only on one lustre client (for now there are two, both use flock). What this message says ? Shall I lfsck the filesystem ? Regards, DT -- http://dtpw.pl/buell [ 25th anniversary of Buell - American Motorcycles ] Linux aleft 2.6.27.29-0.1_lustre.1.8.1.1-default #1 SMP drbd version: 8.3.7 (api:88/proto:86-91) pacemaker 1.0.6-cebe2b6ff49b36b29a3bd7ada1c4701c7470febe ___ Lustre-discuss mailing list Lustre-discuss@lists.lustre.org http://lists.lustre.org/mailman/listinfo/lustre-discuss