An alternative for very large file systems is LVM. It can spread out the load between multiple volumes so that there is less of a chance that the file system favors one volume.
LVM has it's own set of challenges, though. It is another layer of code to the filesystem, that may effect performance. On Wednesday 13 March 2002 07:32 am, you wrote: > I agree If by definition you can only have one I/O operation active to a > UCB, then by supplying PAV's to virtualize, or multipath the UCB you can > get multiple I/O's to the same UCB. > > I have been very reluctant to push use of 3390-9 DASD volumes for SFS > and/or users with large file requirements. For a single user/file this > should not be an issue. Say you have a single repository or file system > that is shared with other guests, than the I/O subsystem becomes a bottle > neck. and when you get to DASD volumes with over 30,000 Cylinders, this > will be even more a problem. > > I would be interested in other peoples Ideas concerning these assumptions. > > > Larry Davis, \|/ > Nielsen Media Research (. .) > VM Systems Programmer ___ooO-(_)-Ooo___ > mailto:[EMAIL PROTECTED] > > -----Original Message----- > From: Post, Mark K [mailto:[EMAIL PROTECTED]] > Sent: Tuesday, March 12, 2002 16:06 > To: [EMAIL PROTECTED] > Subject: Re: PAV Support - any requirement for it ? > > > Ingo, > > Yes, I would say there is a requirement for it, either running in an LPAR, > or under VM. _VM_ has a requirement for PAV. Anyone who wants to build a > large volume and access it from multiple processes with any reasonable > performance has a requirement for PAV. File servers, database servers, > etc., etc. Barton Robinson recommends emulating the smallest DASD devices > possible to get decent performance out of them, due to the lack of PAV > support in VM. That's going to be a real problem for people who have large > files they need to be able to support. > > Mark Post > > -----Original Message----- > From: Ingo Adlung [mailto:[EMAIL PROTECTED]] > Sent: Tuesday, March 12, 2002 11:42 AM > To: [EMAIL PROTECTED] > Subject: PAV Support - any requirement for it ? > > > I'd like to gather your feedback on the requirement for Linux > exploiting Parallel Access Volume (PAV) support available on ESS > (Shark) storage subsystems and its competitors in the market. > > In the past some customers expressed their concern about the data > throughput ESCON attachments provide, which made us think about PAV > support. However, I would appreciate any thoughts about FICON based > storage attachments already satisfying your throughput requirements > or whether you consider PAV exploitation a major requirement > nonetheless ? Any opinions ? e.g. do you see requirements for it > as you can't move to FICON in the forseeable future ? > > I would appreciate your feedback, either offline or to this list. > In any case I would appreciate if you could also depict the business > scenario / solution you expect PAV exploitation being a requirement > for. > > Thanks and best regards, > > Ingo > > ********************************************************************** > Ingo Adlung, > Linux for zSeries - Strategy & Design > > The box said, 'Requires Windows95 or better', ...so I installed LINUX. -- Rich Smrcina Sytek Services, Inc. Milwaukee, WI [EMAIL PROTECTED] [EMAIL PROTECTED] Catch the WAVV! Stay for Requirements and the Free for All! Update your S/390 skills in 4 days for a very reasonable price. WAVV 2002 in Cincinnati (Fort Mitchell, KY). April 12-16, 2002 For details see http://www.wavv.org
