A summary of my original question:
Based on benchmarks which show UFS outperforming advFS under virtually all
circumstances combined with advFS's vulnerabilities in regards to corrupted
file systems, why should I use it?
Thanks to the following for responding with various suggestions and comments:
Goetz Golla
Donn Aiken
Donald Bovee
Larry Magnello
Susan Rodriguez
Alan ??? (lost his last name because my e-mail screwed up that day - sorry!)
Martyn Johnson
Dale Inman
Eric Rostetter
Tony Miller
Lars Bro
Stephen Mullin
Arun Sanghvi
George Guethlein
Apologies to anyone I may have left off. (I know there's at least one. I
heard from a DU UFS engineer pleased as pink at how UFS was kicking butt
and wanted to help me rev the engine even more. Unfortunately I lost his
address!)
Summary of Responses:
Much of the information I received follows. The bottom line is UFS is
faster; advFS has some nice features; advFS has some scary aspects in terms
of corruption and non-recovery issues but is getting better. It's clear
there are a lot of System Managers out there who are afraid of advFS,
either because of personal experiences or horror stories they've heard of
or read in this list.
Detailed Comments:
advfs gives you flexibility in space allocation - volumes can be
added/removed to a domain while it's being used. For some people this
feature was worth its weight in gold. On-line backups from clone filesets
is also a nice feature for those whose storage requirements make it
affordable.
I recevied MUCH confirmation that advfs has some deficiencies in handling
even minor hardware problems. Many said advfs has gotten better over the
versions. Others are still waiting for it to further mature. Many also said
they wouldn't get closer than a 10 foot pole to advfs because they're
constantly reading reports in this list from people using advfs and it's
gone bump in the night. Also frequent complaints of difficulties recovering
advfs from backup. advfs is more complex - UFS is simpler.
Most system administrators are, not surprisingly, not nearly as concerned
about speed as they are reliability. To quote Donn Aiken: "Right data is
better than fast data". Well said.
A good solid RAID configuration is obviously a criterion for any data
warehousing environment. Many people pointed out that I should be using
dual-redundant HSZ's instead of SWXCR. To this I heartily agree. I should
have pointed out that I was just using the SWXCR controller for
benchmarking. All our production machines using HSZ's. I would like to run
all of my benchmarks against HSZ controllers but I don't have a system
available for this right now. I would be very surprised to see advFS
outperform UFS and I really didn't get any responses from folks who would
disagree. I did hear it suggested that advFS could be better for random
access queries as opposed to many of the "full scan" variety, however my
benchmarks did include some random access queries and still UFS was faster.
I heard some sentiment regarding advfs being the wave of the future. Future
truclustering will require advfs. Compaq may drop UFS support in the
future. (Doubtful to me - sounds like Compaq scare tactics ...) Other
companies have similar products to advfs. (i.e. JFS)
An interesting sentiment was that UFS data structures are in the public
domain. AdvFS is "magic". This is the 'ole proprietary vs. open argument.
Of course for us System Managers who've been burned by too many late nights
recovering from too many system, er, "events", religious arguments like
this usually take a back seat to "give me something that works!". I always
felt Digital was overzealous in promoting advFS. My opinion hasn't changed.
They want to lock you in to their "value added" features.
cknorr_at_hops.com
305-827-8600 ext. 238 (voice)
305-827-0999 (fax)
Received on Tue Oct 27 1998 - 22:53:27 NZDT