Creating more smaller volumes is preferred over one or two mega volumes.   As you noted in the included article the exact number depends on the specific situation.   But a SCSI consideration is Command Tag Queue depth (CTQ)  Where each volume/LUN can only process a certain number of outstanding IO requests.  Typical value is 32.  So if you have many VMs on a LUN you are more likely to hit that value, so even though more IO is possible it's been artificially limited.  If you have two volumes, that's 64 possible, and so on.    So going to the extreme of one VMFS volume / VM isn't efficient either.  It gets worse if there are mutiple ESX servers accessing common volumes.  Since at times, one node will lock out all other nodes for certain IO operations.  With only on or two volumes that can become a bottleneck.   Regards, 
Hello Everyone, I am trying to figure out how big I should make my volumes; we have an Equallogic PS4100X and we are running vmware esxi 4.1 (free version) with about 50 vmware images of various sizes (20gb - 300gb).  I am trying to figure out if I should create say two large volumes (Development and Production) and leave it at that, or if I should create my volumes based on how many the individual components can support (mostly the PS4100X). We had a technician that suggested that we run 8-9 vmware images per volume.  However, I dont have any hard facts, written, to back the statement. Is there some math formula that I could use to figure out?  i.e.   ( 8 vmware images needing 4000 IOPS, and the PS4100X supporting 4200 IOPS per volume), etc...  Perhaps the issue is not IOPS, but connections.  Etc.  Whatever the limitation may be? I looked through all the questions and came across a similar question, but I need a statement to the limitation, or a formula to help me compute.  Could someone help me?  This is my first time using a ISCSI, I dont have any experience. [URL] Thanks!! Frank
Best Practice - Volume Size - vmware esxi 4.1 free