My original query:
>We are contemplating the purchase of a new server to replace an
>existing 3/180S, and the low-end Solbourne has a rather attractive
>price tag. The configuration would most likely be two cpu's, something
>around 2 Gb of disk, and 32 Mb of disk.It will probably wind up
>supporting 15 - 20 Xterminal seats and 4 - 6 compute - intensive jobs
>in the background. (On a tough day.)
>My concern with the machine is that it is available only with SCSI
>disks. Does anyone out there have any experience with this machine?
>Does disk I/O tend to be the bottleneck on it?
Apologies for the late summary -- our decision-making process went into
the final hours before my vacation.
Thanks to Paul Graham for forwarding my request to the Solbourne mailing
list. I got a total of 12 responses, two of which were requests for
copies of the info I might receive. One other response said the
filesystem is always a bottleneck on a Unix[tm] system, and the
remaining nine were from satisfied Solbourne users.
--- firstname.lastname@example.org (Joe Carlson), reports 800-1000 Kbytes/sec throughput on a 5/501 with Hitachi DK515C disk drives.
--- email@example.com (Dave Stuit) has a 5/602 with four 1.2 G drives on the internal SCSI bus, used as a print, news and disk server. Not much of a performance problem.
--- firstname.lastname@example.org has a Solbourne with SMD drives, but says that Solbourne's synchronous SCSI would be almost as fast.
--- bit!markm (Mark Morrissey) has a 5/602 with 2 Maxtor drives, which he reports is almost as fast as their 3/280 with SMD drives. The new Solbourne OS should also be a big improvement as well.
--- Stan Hanks <email@example.com> also says that the Solbourne SCSI implementation is faster than SMD in a Sun, at least prior to the 490.
--- bit!jayl (Jay Lessert) has a 5/602 with two SCSI drives, which he claims are 2-3X faster than the internal SCSI drives on a Sun 4/60. The forthcoming release of Solbourne's OS should support symmetric I/O which would further improve I/O performance.
--- Paul Attridge <firstname.lastname@example.org> has a 5/504 server with 1.2G of disk, four processors, and 64M of RAM. Performance with 2 or 3 32 Mb processes, plus interactive logins is good. His guess is that processor throughput would be a problem before disk I/O speed.
--- Costas Kardasopoulos <email@example.com> reports no problems with a configuration similar to the one I described, supporting 6 X-terminals, plus other remote logins.
--- Nigel Mitchem <firstname.lastname@example.org> says that their Solbourne has SMD drives because, at the time it was purchased, SCSI was considered too slow. He also included some guidelines from NCD which describe the memory, processor throughput (in MIPs), swap space, host limits, and network interface needed to support X-terminals.
--- Jeff Nieusma <nieusma@boulder.Colorado.EDU> says that the filesystem is always the bottleneck in a Unix system.
Based on the guidelines Nigel Mitchem sent, I calculated that we would need two CPU's, over 64 Mb of RAM, and another 669 Mb drive just for swap space. Given that, it appears that we can buy Sun SLC's with 104 Mb local disks and a Sparcstation+ server for less than the full-blown 5/501 and X-terminals.
Many thanks to all who responded.
This archive was generated by hypermail 2.1.2 : Fri Sep 28 2001 - 23:05:58 CDT