Thanks for the warning. I do plan on minimizing the number of LUNs, but my boss asked the question and I wanted to be sure to have the /right/ answer instead of the /right-now/ answer.
> -----Original Message----- > From: Roger Seielstad [mailto:[EMAIL PROTECTED]] > Sent: Friday, October 04, 2002 7:51 AM > To: NT 2000 Discussions > Subject: RE: Basic SAN question > > > Chris, > > Most vendors will allow you to slice and dice a SAN array > into as many LUNs of whatever size you want. Its absolutely > the wrong thing to do, but it certainly can be done. > > Any time a phisical platter is partitioned, you're going to > take a performance hit - simply put, the heads can't be in > two places at once, so if two systems are trying to access > data which is physically on the same platter, but logically > on different LUNs, there is head contention, and one of the > two must wait for the other to finish "using" the heads, and > then pay the additional price of a head seek across the > platter to its assigned set of cylinders. > > In the case of your single 500GB RAID5 set in your SAN being > split into 300/100/50/50, you have in reality created 4 > partitions on each spindle, with 60%/20%/10%/10% split on > each spindle. With a large number of platters, and larger > stripe sizes, its theoretically possible to reduce the > chances of contention within the SAN, but realistically > speaking, chances are there is going to be some contention, > and therefore some performance hits associated with managing > your disks this way. > > Its one of the lies^H^H^H^H omissions commonly done in the > sales pitches of the big storage vendors. > > ------------------------------------------------------ > Roger D. Seielstad - MCSE > Sr. Systems Administrator > Inovis - Formerly Harbinger and Extricity > Atlanta, GA > > > > -----Original Message----- > > From: Chris Levis [mailto:[EMAIL PROTECTED]] > > Sent: Thursday, October 03, 2002 2:07 PM > > To: NT 2000 Discussions > > Subject: Basic SAN question > > > > > > If you have a RAID-5 array of (let's say) 500GB, can you > > create LUNs of an > > arbitrary size to be presented to the servers? E.g, a 300GB, > > a 100GB, and > > two 50GB? Or is there a convention that all LUNs have to be > > a uniform > > size? > > > > Thanks! > > > > > > > > > > > > ___________________________ > > Chris Levis > > Applied Geographics, Inc. > > > > ------ > > You are subscribed as [EMAIL PROTECTED] > > Archives: http://www.swynk.com/sitesearch/search.asp > > To unsubscribe send a blank email to %%email.unsub%% > > > > ------ > You are subscribed as [EMAIL PROTECTED] > Archives: http://www.swynk.com/sitesearch/search.asp > To unsubscribe send a blank email to %%email.unsub%% > ------ You are subscribed as [email protected] Archives: http://www.swynk.com/sitesearch/search.asp To unsubscribe send a blank email to [EMAIL PROTECTED]
