Impending doom (for our filesystems, anyway)

Impending doom (for our filesystems, anyway)

Over the past year or so the space usage on our research and web filesystems has pretty much doubled to the point where we’re dangerously close to running out of space. There’s currently about 1TiB of filestore available of which less than 10% remains unused.

Teaching filestore, however, has barely grown at all during the last year. I attribute this primarily to quota control, but also to the regular turnover of undergraduate students.

Fortunately we saw this problem arising quite a while ago, so we’ve had time to purchase new storage and infrastructure that should alleviate this problem and make it easier for us to expand the storage availability in the future.

Our new system consists of a pair of Sun StorEDGE 3511 arrays attached by fibre channel to our existing Veritas cluster. We’ll use VxFS for the filesystems, which could lead to some interesting new technologies like filesystem checkpointing; we could have a mount point of /yesterday to allow users to retrieve their files as they were at some point during the previous day, thereby reducing the need for us to do tape restores. VxFS also works quite happily with large filesystems, unlike Solaris UFS. The only problem we’ve found is that VxFS doesn’t support hard linking directories, but that’s not something we commonly, if ever, want to do. We also initially had problems integrating VxFS with the Solaris quota system over NFS, but we soon fixed that the “fun” way 🙂

Currently the research and teaching servers have locally attached filestore, which means if we have a hardware failure in one of the main servers we’re unable to get at user filestore from any other systems (without moving cables). The new solution provides NFS mounts of the filestore directly to each of the servers, which will allow files to be accessed via secondary machines should one of the main servers die. This is all part of our long term plan to increase the resilience of our systems.

One other interesting point to note is the use of the Solaris automounter to individually mount user home directories. Soon there’ll be mounts a bit like this all over the place:

resfs.cs:/home/cur/tdb 1.5T 54G 1.4T 4% /home/cur/tdb

Which will make things much more interesting!

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