RE: [BLAST_SHIFTS] [BLAST_ANAWARE] /home/blast

From: Ernie Bisson, MIT Bates Linear Accelerator (BISSON@AESIR.mit.edu)
Date: Wed Jun 16 2004 - 12:01:11 EDT


>Hi,
>
>While we are at it, I'd like to put in my 2-cents worth:
>
>Although, we are supposed to use the scratch area for large (and
>replaceable) files, it is apparent that the usage of /home/blast
>is always close to its maxima (~20GB). Somehow, people need to
>use their home directories rather than the scratch area, thus we
>manage to fill it up to 100.0% from time to time. For one thing,
>it is accessible from all machines (read convenience!). I -try-
>to keep my usage below 0.5GB, which is not small. And there are
>many other users who have similar usage rate (see the attached
>figure for all of 80 accounts.) No matter what we do, the usage
>will hardly be below 60%-70% (I'm optimistic!) which is a
>comfortable level considering the possible fluctuations.

All of the BUD's have ~240GB of scratch area available. In order to avoid
excessive cross-mounting of partitions, it was originally decided to choose
one of them (bud24) to mount on all the BUD's. I will hard mount that on all
of the remaining dblast systems right now. This should alleviate the need to
store large (and replaceable) files on /home/blast. So the cross-mounting is
kept to a minimum at any given time, I will then figure out how to automount
them (rather than hard mount).

Do the SPUD's need access as well?

Also, Michael asked me the other day if I could mount the remaining /scratch
areas on all the BUD's as well. Is this really necessary? If so, then I will
make them available for automounting as well.

>After this introduction, here we go: Can we get a considerably
>larger disk for /home/blast? After all it is only 20GB, and we
>are at the age of 400GB disks (see the new Seagate SATA drives -
>nowadays, the minimum 3.5"-disk capacity is well above 20GB!
>20GBs are used for mp3 players!). I'm sure the price (even for
>SCSI) is not an issue here, if we compare it to the maintenance
>and productivity loss due to the disk-full-down-times which
>happens every now and then...

As Doug stated in his reply, having to backup very large areas is the concern.
I'm sure a good portion of a 400GB partition would get used in a short time.
This would make FULL backups much more time consuming than they already are.
Currently, I backup ~175GB of potentially used space (meaning: if all of the
partitions I backup were full it would be ~175GB of data). My FULL backup from
last weekend contained ~100GB of used data. The /home/blast area (~20GB) takes
3.5-4 hours itself to backup.

I assume his mention of disk mirroring refers to RAID disk mirroring. This of
course would not provide backup protection against files deleted by mistake,
which has happened several time in the case of /home/blast.

Ernie



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