Jeffrey Hutzelman <[EMAIL PROTECTED]> wrote:
}> I'd love to be able to solve the disk space management availability
}> issue once and for all (at least for a few years or so) by making available a
}
}> terabyte of disk space from either one or a handful of AFS file servers
}rather
}> than 8-16 GB. While such a centralized model may suffer from the advantages
}> of having data distributed across many file servers, it would have the
}possible
}> advantage of being easier to manage.
This similar to our setup. We currently have 11 FileServers
(10 DECstation 5000/240or260s, 1 AXP3000). Typical config
is FDDI, 3 SCSIs, 18 disks (1/2/4 GGs over the years).
Our 3 AFSdb machines do nothing else. We're approaching
1/4TB at present (with demand for considerably more).
We have ~1000 clients and ~35,000 users [thanks goodness
for Ultrix and AFS source licenses!]
}We have around 422GB online now, scattered across around 40 fileservers.
}That works out to an average of 10GM per server, but that number is
}misleading, because many servers still have smaller, older disks, or
}belong to specific research projects (and thus can only be used to hold
}that group's volumes).
}Our typical server setup is a 24-28MB Sparc 1+ with two SCSI busses,
}and a maximum of 4 disks per bus. The largest single disk we normally
}put on AFS is approximately 4GB, so we can generally get anywhere from
}28-32GB on a single server. Even with Sparc 1+'s, that gives us a
}reasonable level of performance.
}
}Once thing I'd consider, in your position, is what happens if one of your
}servers has to go down. With as many servers as we have, we generally
}have a few scheduled to go down each month for one reason or another -
}new disks, disk replacement (with 400+GB online, occaisonally a drive
}goes bad). Additionally, if you put all your disk space on one server,
}you essentially lose the ability to replicate databases and critical
}volumes for fault tolerance as well as load balancing (we currently
}run 3 database servers, which is reasonable for our size. Andrew,
}which has nearly an order of magnitude more users than we do, runs
}with 5. You probably should be doing the same).
We just moved them onto 3 machines doing nothing else -- this
was a big reliability plus for us -- esp. since the file servers
take so long to come up (fsck/salvage/volattach).
}With reasonably fast servers, I'd reccommend not putting more than,
}say, 50-100GB per server, and then only if your network can keep up
}(it sounds like you don't have that problem).
What I'd like to do is move to a smaller number of FileServers,
but I'm unsure how much data you can put on an AFS server.
What I have in mind are AXP1000s with a pair of the 3 channel
RAID controllers which would give 144GB of space.
John
--
John Hascall ``An ill-chosen word is the fool's messenger.''
Moderator, comp.unix.wizards
Systems Software Engineer, ISU Comp Center + Ames, IA 50011 + 515/294-9551
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