> Anyone have a particularly large HSM environment and been using it a while?
We have been using ADSM HSM for years, principally for archiving system log files and like stuff, which we retain for five years. HSM makes this practical, and affords obviousness of the stored data (unlike ADSM Archive) and ready retrievability. Suffice to say we have many gigabytes of it. For this it works nicely. We had early on anticipated rolling out HSM more generally - but then realized the problems. HSM is a DISASTER when used over NFS... Picture gigabytes of data flowing into a file system over NFS; then the file system fills. Automigration makes what space it can - but that's not enough. Reconciliation is now running on the file system, but that can take up to 2 hours. Now the file system is full, and the HSM session is wedged. This causes *all* NFS service from that system to cease, and wide-spread chaos ensues as even innocent 'df' commands issued on other systems which have that file system NFS-mounted hang, and can not be freed until the NFS server again responds. This, in combination with fragmentation issues and other factors, caused us to deem HSM not for civilians. HSM has its uses, but is awfully Rube Goldberg. You may first want to consider file systems which autocompress data stored in them. Richard Sims, BU
