Hi *SMers At server version 5.3, there is an undocumented feature change to the FILE devtype (see IC48331) such that the minimum write size is now 256K. For most files, this is not a problem. However, if like us you have a disk based directory storage hierarchy (random_access -> disk-sequential_primary; disk-sequential_copypool), then this is a disaster. We used disk sequential so that we could reclaim aggregates. On average, we normally saw a total disk usage of 5-10GB max, with each full volume initially reading 100%, and containing 40,000+ directory objects per 64MB file.
Now we are seeing a newly written Full volume (from reclamation) with a maximum of maybe 0.7%, and containing as many as 400 directory objects in a 64MB file. Required disk space naturally has gone through the roof. The circumventions in IC48331 have not had a terribly significant effect - a few tenths of a percent only. For the moment, we are increasing the size of the DIRS random access diskpools, not migrating out to serial disk, and ignoring the (hopefully minor) hit on fragmentation. But this still leaves the copypool. At one time, we used to backup up the DIRS pools to tape. Then we tried to reclaim a tape volume that must have been in use for more than a year, but still only had a percent or two used. After a few days of continuous reclamation we gave up, and deleted the volume, then discarded the tape. So for pure DIRS storage, tape is not a good option. So far, the only useable circurmvention we can see is to use server-to-server virtual volumes for copypool, and not to use seqential disk file for primary storage. Is there a better way? Regards Dave I think it's a beautiful day to go to the zoo and feed the ducks. To the lions. ____________________________________________________ Dave Frost Technical Consultant SunGard Availability Services (UK) Limited London Technology Centre Heathrow Corporate Park Hounslow UK. TW4 6ER Tel: +44 (0) 800 2799 166 Fax: +(0) 20 8080 8112 mailto:[EMAIL PROTECTED] ____________________________________________________ Keeping People and Information Connected (TM) http://www.availability.sungard.com
