>> Hi, >> Is anyone on this list familiar with iSCSI? I was wondering if >> it'd be possible to setup a Logical Volume as an iSCSI target and export >> it over an IP network for other clients to use. I'm interested in >> setting up an IP SAN, where the storage devices are logical volumes >> managed by LVM. There's this company called SANRAD that makes a hardware >> device called an iSCSI switch. The iSCSI switch is connected to a pool >> of storage disks on the back-end and to a bunch of servers on the >> front-end. It uses logical volume management to carve out logical disks >> from the back-end storage disks, then exports these using iSCSI to the >> front-end servers. (Check out their website http://www.sanrad.com for a >> nice flash movie of this architecture). Anyways, some fellow classmates >> and I are interested in building such an iSCSI switch in software, using >> LVM and other opensource components. Any feedback would be greatly >> appreciated. >> Regards, >> Kai-Min Sung Ignoring efficiency issues, you should not have any problem putting together a Linux Server with lots of internal disk space, then using LVM to manage that space, and have iSCSI target software share it out to a small collection of iSCSI initiators. FYI: I have only tested iSCSI exporting of partitions, not LVM LVs. I assume you know that iSCSI was formally accepted earlier this year. I don't know if there is a OSS target and initiator pair available yet or not that implements the formal spec. The Intel reference implementation appears not to have been updated yet: http://sourceforge.net/projects/intel-iscsi >From my testing of the earlier rev levels (v8, v12, v16) there is not much vendor compatibility and definitely there was not rev. level compatibility. If you care about Win2K, MS is supposed to be releasing a iSCSI initiator driver in the summer. It will meet the formal spec. not the draft releases. BTW: From an efficiency perspective you should check out iSCSI NICs. There is a lot of TCP/IP overhead associated with iSCSI, and these NICS are designed to eliminate that portion of the CPU load. I have not used them, but I assume the present a SCSI interface at the PCI bus level. FYI2: Snapshots require LV support _and_ FS support. In what you are describing, LVM would provide the LV aspect, but you would need to support only filesystems which have a freeze capability. I use xfs and I know it does. LV resize would also need corresponding FS support. Greg -- Greg Freemyer _______________________________________________ linux-lvm mailing list linux-lvm@sistina.com http://lists.sistina.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
