The sustained write rate of a 3590 drive is 15 MB/sec at the head. You multiply 15 times your compression ratio to get the sustained transfer rate through you adapter. I have saturated the arbitrated loop (FC-AL) of a fibre 3590 with DB2 backups (60 MB/sec), but that was highly compressible data. The real question is: what are the requirements of your environment? If you need the full read/write capacity of your drive for backups and/or restores, and you compress highly compressible data at the drive, and you can actually generate that much I/O in your system, then 60 MB/sec of bandwidth is needed per drive. If your cards are attached to a switch, they have 100 MB/sec. maximum bandwidth, so each card can sustain 1 2/3 drives at saturation.
It is difficult to push data as fast as a 3590 can take it. The client disk and CPU will likely limit your ultimate throughput. The best I have yet attained was 114 MB/sec to 3 3590 E drives with DB2 reading from two Sharks and transferring the data over an SP switch. The switch was the limiting factor, but the Winterhawk II DB2 node was nearing its CPU limit (4 CPUs). Orville L. Lantto Datatrend Technologies, Inc. (http://www.datatrend.com) IBM Premier Business Partner 121 Cheshire Lane, Suite 700 Minnetonka, MN 55305 Email: [EMAIL PROTECTED] "Cook, Dwight E" <[EMAIL PROTECTED]> Sent by: "ADSM: Dist Stor Manager" <[EMAIL PROTECTED]> 12/31/2002 10:35 AM Please respond to "ADSM: Dist Stor Manager" To: [EMAIL PROTECTED] cc: Subject: 3590 (E or H) drives per FC interface (6227) ??? I've looked through the archives and can't find much. I've waded through IBM's web sites and can't find specifics... Has anyone found any recomendations on max number of 3590's (FC attached) per FC card on host ? Environments I'm looking at are 7017-S70's that have a max of 4 FC cards (6227's) per system. I'm already driving my ESS storage with 2, that would leave me with 2 cards to drive 8 tape drives. (or maybe mix everything together and let the device drivers balance the loads ????) So is anybody driving 4 3590's off a single FC adapter and if so how are your data transfer rates look with 1, 2, 3 & all 4 drives running ????? Math says 1Gb (1024Mb/sec) FC card is 128 MB/sec or 450 GB/hr 100 MB/sec burst data transfer rate of 3590 is 351 GB/hr so really 1 card per 1 drive but 4 cards could drive 5 drives... NOW... With 3590-B1A's & E1A's that are SCSI attached (one drive per one scsi adapter) I see migrations run at B1A'a 22-ish GB/hr E1A's 32-ish GB/hr Now SCSI attached drives have a burst rate of 40 MB/sec 140 GB/hr So on my E1A's I see migrations run at 23% of the burst rate So if I expect the same from FC, migrations across FC would be at 23% of 100 MB/sec or 23% of 351 GB/hr or 80 GB/hr if I have one drive per one FC card... So with all that said, a single FC adapter should be able to drive five and a half (5.5-ish) FC 3590-E1A's or H1A's and run at least as good as SCSI attached at a one-to-one atachment... right??? Anyone have any thoughts... (other than I need a vacation) Dwight E. Cook Software Application Engineer III Science Applications International Corporation 509 S. Boston Ave. Suite 220 Tulsa, Oklahoma 74103-4606 Office (918) 732-7109
