John, The Gresham Storage Director provides both iSCSI and/or FC connectivity for your backup servers and manages physical tape and other devices off the back-end. iSCSI works well with this and has many good attributes including using existing infrastructure for remote connectivity. We have connected a backup server in Texas to a Gresham box in the UK for example, and performed a backup all the way through to physical tape in the UK over a VPN tunnel.
Performance is the issue however. WAN performance is impacted by many things, not to mention the number of "hops" to get to the final destination along with whether you are sharing the performance of the WAN connection with other things, but functionally it works fine. In a local tape environment, you can use iSCSI over a 1Gb Ethernet network and we generally see about a 50-80MB/Sec data rate (megabyte not bit) with the Gresham box in this environment. You might say that this doesn't sound very fast but in reality a given backup server running from internal disks usually can't push data any faster than that anyway. Therefore put each backup server on it's own private network if you wish. I would say that if you don't have a high bandwidth requirement, iSCSI over 1Gb Ethernet might be a good low cost solution in the configuration mentioned above. However, 10Gb iSCSI adapters are now available and should be able to give you performance equivalent to 4Gb FC but we are seeing differences in performance on different adapters and will be testing this more before we make a selection. The other problem with 10Gb iSCSI right now is that they are still charging as much or more for these adapters and switches than they are for 4Gb FC so there is no real incentive from a cost perspective. Hopefully this will change in the future. Regards, Tom Wright tel: 512-407-2609 -----Original Message----- From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED] On Behalf Of Schneider, John Sent: Thursday, July 10, 2008 2:20 PM To: ADSM-L@VM.MARIST.EDU Subject: [ADSM-L] iscsi world as it relates to TSM world Greetings, There are a couple people at our company that contend that FC is going away, and in a very short time everything will be iscsi. I am afraid I am completely ignorant about iscsi as it relates to tape traffic. My questions are: 1) Can anybody tell me what is going on in the iscsi world around tape? 2) Are there iscsi software/hardware solutions for Windows and AIX (or TSM platforms) attached tape? 3) Are there tape drives/libraries with native iscsi support, or are converters necessary? 4) Have any of you converted from a SCSI or FC tape environment to iscsi? If so, what were the gotchas? Thanks in advance for the input. Best Regards, John D. Schneider Lead Systems Administrator - Storage Sisters of Mercy Health Systems 3637 South Geyer Road St. Louis, MO 63127 Phone: 314-364-3150 Cell: 314-486-2359 Email: [EMAIL PROTECTED] This e-mail contains information which (a) may be PROPRIETARY IN NATURE OR OTHERWISE PROTECTED BY LAW FROM DISCLOSURE, and (b) is intended only for the use of the addressee(s) named above. If you are not the addressee, or the person responsible for delivering this to the addressee(s), you are notified that reading, copying or distributing this e-mail is prohibited. If you have received this e-mail in error, please contact the sender immediately.
