Madia multiplexing - Clarification
I have read all boord about multiplexing but I don´t understand so much.
I use NBU 6.5.2 for Windows Server 2003 X64 with a Tape Library HP StorageWorks 4080 LTO4, with 48 slots and 2 drives.
for example:
For 10 clients (about 600 GB) I have 1 Policy with 36 Schedules. Each schedul on 1 Tape.
How can I use multiplexing for a good backup speed?????
Sorry, but you put the statement there!! ( :smileywink: ):
ebodykid wrote:(all experts correct me if i am wrong on this part) If your boss is worried about losing multiple backups on a tape, this should not need to be a concern unless you have allowed different retentions to be written to the same tape. If your jobs kick off and run on monday, and have a rention of 25days, that tape shouldnt be written to again until the jobs have expired on it. Therefore, when backups run on tuesday it should grab a different tape because the retention date would then be 25 days from then (or 1 more than mondays). You would essentially have a tape rotation as you are looking for, but allowing netbackup to manage the volumes to prevent 96 errors....
It is the retention periods (e.g 1 month, 2 years etc) that aren't mixed on media (unless specified otherwise) & not retention or expiry times - e.g. for a retention period of a month - if a tape is written to at the start of the month, it can & will be wriiten to by any other save of that same retention period until it is full - the tape will then not expire until ALL the images have expired (which in this instance would be a month AFTER the last image was wriitten).
As far as the original (?) question, the most schedules we have got, or ever had, in our policies is 9 (& this could probably simplified a great deal):
Monday Differential
Tuesday Differential
Wednesday Differential
Thursday Differential
Friday Differential
Saturday Cumulativve
Sunday Differential
Monthly Full (runs on Saturdays in place of the cumulative)
+ a one off full used for 'manual' backups as necessary.
To facilitate this we have a volume pool for each of the above - not necessary but it works!
Monday thru' Thursday have a monthly retention but stay in the library - these are constantly written to when available & left to expire 'naturally', we don't specify which tapes are in each pool, they are assigned automatically by NetBackup from scratch when required.
Friday thru' Sunday also have a monthly retention, but are removed off-site each Monday & aren't returned until they've expired.
Monthly saves have a yearly retention & are removed once saves are complete & again are not returned until they've expired.
In all of the above instances we don't tell NetBackup which tapes to use, but if we need to know then NetBackup can 'tell us'. Also, we could remove each days tapes as & when they've been used & obviously they won't get used again until they are returned. Essentially, you don't even need any extra volume pools than what are there by default - take Mondays tapes out on a Tuesday & put them in the "Monday1 box"
- some compartmentalisation would be useful, but as already posted (& as I think you are finding out) if you start to try & micro-manage your environment then you are only making more work for yourself & any issues that you encounter are going to be that much harder to identify & correct.
I would suggest you reduce your schedules to at most one a day (Mon-Sun), maybe a weekly, a monthly & an annually? You will find it is much much easy to maintain.
