An interesting difference in philosophy. We use HSM less for backups
and more for space management. The backup capability sounded attractive
initially, but we quickly found that with some application batch running
almost 24x7 there were too many cases where the timing of autobackup
and/or the number of cycles needed made HSM backup a bad fit for us. On
the other hand, being able to move idle data the users are unwilling to
delete to duplexed ML2 has become a significant savings for us for DR.
The data is completely covered for DR and yet rarely needs to be
touched. If the migrated data were still on DASD, it would have to be
repeatedly processed and dumped by daily DR point-in-time backups and
add significantly to the cost of daily DR processing.
If we had the luxury of our own DR hot site and could afford the
required bandwidth, we would look for DR solutions that minimized
dependency on tapes and rethink our current HSM strategies as well.
R.S. wrote:
Hal Merritt wrote:
Forgive me guys, I don't get it. All HSM does is move data from cheap
DASD to expensive tape and back. I doubt it even does much compression
on modern DASD or tape. It just shuffles data around. Yes, HSM offers
some nice management features, but are they worth the price?
We have about 2 TB over two sites. We look at HSM from time to time, but
just don't see a business case. We end up just buying more DASD.
Unless, of course, you are a competitor. If so, then by all means do
things just because that's the way you have always done things ;-) Our
sales people thank you.
It depends. Sometimes (2TB is good example) it is good to have
everything on DASD, including backups, tapes only for DR, data input,
etc. Second hand DASD are good for such purposes. Price of GB is usually
less than 10% of new one.
However, when you grow up with the capacity you'll find it's more
cost-effective and more convenient to use tapes. Modern tapes. It is not
very expensive when you carefully choose the configuration.
Regarding HSM license: this is a tool for backups. Without it (or
competitive products like FDR) you have to keep track of every file's
backup manually. Error prone. With HSM you set up managament classes,
some ARCCMDxx and sleep safe.
Migration facility is an option, which need not be used.
--
Joel C. Ewing, Fort Smith, AR [EMAIL PROTECTED]
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