On Thu, 11 Jul 2002 15:35:22 David L. Cassell wrote: >Abe Anon <abe_anon@HOTMAIL.COM> wrote: >> Please pardon the off-topic message. Perhaps someone on the list knows >about >> these things. > >Umm, is anything really OT for this group? Storage on SlowLaris seems >reasonably close, considering some of the topics. > >> In the mainframe world there are products that monitor disk access and >> automatically move files that aren't accessed much to secondary >storage, and >> then automatically move them back if there is an access request. All >this >> happens transparently to the user.

Just a brief mention, here. The primary product used in the "mainframe world" for migration/restore is called IBM DFHSM. It is typically configured to migrate files to secondary(usually disk) -and- tertiary(usually tape) storage.

Restore from disk is relatively transparent to the user. Restore from tape can be anything _but_ transparent to an interactive user. It often freezes the user's process while a tape mount request is issued. Even if a tape drive is available, this can result in a sizable wait. One might assume that HSM would be configured to gobble up only large unaccessed files, but I've seen it usurp little parm files, tiny flat files, PDS's using maybe 2 tracks (about 115k), etc.

In fact, there are probably some folks out there that feel that "DFHSM does more to bugger productivity than any other software product in the mainframe environment". I myself have had to write batch programs to restore datasets so users could run interactive applications unhindered.

I have no idea how migration software works in a Solaris environment. But you might wanna do a bit more than assume that "All this happens transparently to the user", regardless of any migration software vendor's claims. I don't think the typical behavior of DFHSM on the mainframe is a good "model".

Cheers, Puddin'

****************************************************** *** Puddin' Man *** Pudding_Man@lycos.com ******** ******************************************************;

>> >> We could sure use such a thing on our Solaris machines. Does anyone >know >> about this? Can they point me to some good information? > >There's a slew of such products. Look up some of these: > >everStor >IBM Tivoli for Solaris (no, really!) >Hallogram ADSM >Sun's own HPSS and ADSM and StorEdge >Legato Networker has a Sun client now > >and there's probably another 20 I haven't heard of. > >HTH, >David >-- >David Cassell, CSC >Cassell.David@epa.gov >Senior computing specialist >mathematical statistician >

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