At 11:18 AM 2/5/93 -0600, Doug Engert wrote:
>Is anyone using optical disks on an AFS server for the AFS
>partitions?
>
>There are a number of Optical disk jukebox devices with a disk
>cache which claim to to attach to a Sun of RS/6000 and appear as
>a large disk.
>
>If the claims are true, using one of these for an AFS partition
>could provide large amounts of cheap storage with all the
>advantages of AFS.
>
>There are a number of vendors of mass storage archiving systems
>which provide both the optical disks and a server with lots of
>their own server software. That's not what I want. I want to use
>our current Sun servers with our current AFS 3.2.
>
>
>(Looking back at my mail, I noticed that [EMAIL PROTECTED]
>asked this same question on July 10. I do not recall seeing any
>responses to that inquire.)
>
> Douglas E. Engert
> Systems Programming
> Argonne National Laboratory
> 9700 South Cass Avenue
> Argonne, Illinois 60439
> (708) 252-5444
>
> Internet: [EMAIL PROTECTED]
I just finished a semi-rigorous investigation of this matter. Regular AFS
limits you to 26 (vicepa thru vicepz) partitions per server where each
partition is less than or equal to 2 GB. This limits your ability to
hook up a jukebox to an AFS server of any make or model. That is, it makes
no sense to hook-up a 144 platter, 90Gb HP jukebox to an AFS server because
you can only use 52 Gb (26 x 2 Gb) of it. If you buy the 60 Gb version of
the HP jukebox, you need to make 4 platters (7 sides, the 8th remains
blank) look like a single vice partition. This makes each vice partition
(7x290Mb = 2 Gb) the proper size. I have quotes stating that the cost for
a 60 Gb, 4 drive HP jukebox with SS2 CPU is $80,000 or $1550/Gb. I can buy
36 Gb of magnetic disks (6x2Gb disks per SCSI, 3 SCSI per CPU) with a SS2
at $1800/GB. Since the magnetic solution doesn't have the slow response
time or robotic problems of a jukebox, we decided to postphone getting a
jukebox. ALso, if you opt for the above type of jukebox solution, make
sure the jukebox drivers are of the type that truly emulate magnetic disks.
If not, it might not work.
The only vendor with a true jukebox solution for AFS is CDC. They have
converted their FARM migration software to work with AFS under CDC's
version of UNIX (e.g. not IRIX) on MIPS-based workstations. The quoted
price for this solution is at least $1800/GB plus $20k/yr maintenance.
ALthough they seemed to have solved all of the technical problems of
working under the umbrella of AFS, again, the price does not seem to
justify the possible headaches (e.g. weird UNIX, robotics, weird CPU),
etc..
We at NIH are staying with magnetic for the coming year. Hopefully, next
year we can justify getting a high-density tape silo that will work with
CDC's FARM product under IRIX (not CDC's home brew UNIX) on true SGI
workstations.
I wish I had better news.
Ron Levin
Acting Chief, Multimodality Radiological Image Processing
=================================================================
Ronald L. Levin, Sc.D. E-mail: [EMAIL PROTECTED]
13/3W13
BEIP/NCRR
National Institutes of Health VOX: (301) 496-4454
Bethesda, MD 20892 FAX: (301) 496-6608
=================================================================
