montanaro@crdgw1.ge.com (Skip Montanaro) (07/27/90)
Our group of 10-15 people currently gets most of its /home disk space from two Encore Multimaxes maintained by a central support group. In order to get us off their machines, they are willing to buy us some storage for our group's file server. Their current proposal is to add a Xylogics 7053 and two 2.5 GB disks (Hitachi?) from NPI to our 3/260. Our client computers consist of nine 4/6[05]GX workstations, each with 16MB of physical memory and 104MB local disks containing root and swap. We have a few other odds'n'ends, such as a diskless 3/60, a couple diskless 3/260s, and a 386i (with disks). My feeling is that, without some reinforcements, the 3/260 file server will be overburdened with the increased disk load, even though most (and eventually all) clients will have local root and swap partitions. My alternatives appear to be: 1. Go with the proposal as it stands and see what happens, making adjustments as we go, 2. Purchase an extra 7053 and turn one of the other 3/260's into a second file server, 3. Purchase an I/O subsystem accelerator of some sort, such as OMNI Solutions' or Legato's products, 4. Upgrade to a full-fledged file server, such as an Auspex NS5000, or 5. Scatter large external SCSI disks (like HP's 660MB or 1GB disks) around the 4/6x's in our offices, effectively making each share some of the disk load. If I knew for certain that something like an Auspex was in the cards, I'd opt for SCSI disks compatible with it (HP 660MB now, 1GB later), and move them when the file server arrived (a combination of #5 this year, followed by #4 next year). Due to its expense, however, an Auspex would likely be shared with a larger organization, with attendant complications in evaluating, ordering, and maintaining it. I am in the process of estimating our group's NFS request pattern on the Multimaxes using Encore's server_stat program. If the write request percentage is not high enough, then an NFS write accelerator like Legato's Prestserve probably won't help much, although OMNI's product would probably still help. I'm pretty confident that Sun-3s can serve Sun-4s, in principal, if you can drive the CPU load down by either replicating CPUs or offloading the CPU with special-purpose I/O subsystems. (After all, the Auspex NS5000 has a Sun-3 VMEbus-based CPU.) I would appreciate feedback from people with any suggestions. The Sun-3 to 4/6x route seems pretty common these days, so there must be some useful experience out there. Here are some questions we can't currently answer and/or won't be able to investigate thoroughly in the time we have available: 1. How bad would the added noise and heat be with large external SCSI disks hung off 4/6x's? 2. Would something like the OMNI or Legato accelerators allow us to use SCSI disks instead of the more expensive (and less flexible) SMD disks? 3. Sun doesn't currently maintain the proposed configuration. What alternatives are there for short turnaround (< 24hr) maintenance? 4. What other architectures are we neglecting? SPARCserver-1s with several large SCSI disks come to mind. What kind of experience have people had with them? I will summarize the responses to sun-managers and sun-spots. Thanks, Skip (montanaro@crdgw1.ge.com)