From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED] On Behalf Of Mike Eggleston >I know that TSM can do both serverfree and lanfree. My >impression of these is that for lanfree the client node >asks TSM over the network where to place files. The TSM >server tells the node and the node talks to the tape >drives directly.
That is essentially correct. >Since I have four tape drives (that I can >put onto the SAN fabric) then only four nodes can backup >at once? Yes; you can only have as many concurrent LAN-free sessions as you have tape drives available. >With serverfree where the TSM server talks to the ESS/shark >directly, how does TSM get things that are inconsistent >like database files that have potentially changes in >memory? It doesn't. Remember that LAN-free and server-free backups are available for TSM's backup/archive client, but not for all of the specialty backup clients such as TSM for Mail and TSM for Databases. >Also, since TSM does not know the end platform, >how can TSM backup files? Does it only back up blocks and >the client must ask for enough blocks to make up the files >it wants to restore? The way that server-free backups happen is that TSM makes use of an application like Tivoli's SANergy. SANergy creates an internal NFS mountpoint with a chunk of SAN-attached disk that TSM's disk-based storage pool uses and mounts the client's chunk of SAN-attached disk onto that mountpoint. TSM backs up files across the mount. It makes for *fast* backups, since the bottleneck in this case is the bus speed of the storage unit's disk controller. Metadata about the backed-up files is sent from SAN disk to the TSM client (via fiber) to the TSM server (via the LAN), but no data moves across the LAN or the SAN. -- Mark Stapleton
