Re: RAID Test in the works

Joe Lumbley (jlumbley@netcom.com) wrote: : Hi, : We've all seen lots of discussion in this group about the pros : and cons of RAID disk systems. We've seen lots of opinion and anecdotal : evidence, but so far nobody's posted anything definitive. I'd like to : develop some more usable data, and I'd appreciate ya'lls input on designing : a test of RAID. [ stuff deleted ] : For each of ([normal SCSI],[non-raid independent drives],[RAID3], [RAID5]) : DO : Run standard disk benchmarking tests in Unix filesystems for both : normal SCSI and RAID devices. Will use Bonnie and iozone : tests. : Run following tests on newly-created files in dbspaces : Load: Load a 100,000 row table from a flat-file : Flatfile lives in normal SCSI filesystem : Read: Unload this file to /dev/null : Update: Update 10,000 rows of the table (non-indexed) : Copy: INSERT into new_table SELECT * from old_table : (both tables in same dbspace) : Delete: Delete all rows in the table : Between each test, stop and restart the engine to make sure : the buffers are empty. : DONE [ stuff deleted ] : Am I missing anything? I believe that this will cover most of the areas : needed to look at the effectiveness of this implementation of RAID. If anybody : has any ideas for additions, changes, or modifications, please post them. I'll : post my results if anybody's interested. I'm sure you have thought of this, but as you have expressed your tests, it sounds as if most of the disk updating should take place at database shutdown time, and it is not clear whether you intend to include this in your timings. You don't say whether the HP hardware allows you to configure the RAID blocksize, but this can be a significant contributor to performance (or lack thereof). You also appear to only be testing sequential access in the OnLine tests, whereas sequential access and random access are likely to have different performance profiles, particularly on update (disk update that is, not SQL UPDATE). -- graeme -- Disclaimer: The author's opinions are his own, and not necessarily those of Pyramid Technology Ltd. or Pyramid Technology Inc. --------------------------------------------------------------------------- -m------- Graeme Sargent Voice: +44 (0)252 373035 ---mmm----- Senior Database Consultant Fax : +44 (0)252 373135 -----mmmmm--- Pyramid Technology Ltd. Telex: Tell who??? -------mmmmmmm- Farnborough, Hants GU14 7PL Email: graeme@pyra.co.uk --------------------------------------------------------------------------- We have the technology. The tricky bit is learning how to use it.