netbackup duplication from disk to tape using slp and destaging
hello all, this is my first post but have been looking at this forum for sometimes now. basically here is my env:
3 sites (netbackup 7.6.1)
A (remote). Media server + MSDP
B (HQ). Master, Media server(B1) + MSDP, 4 tape drives LTO5, Basic disk for Destaging to tape.
Media server(B2), Basic disk for Destaging to tape on B1
C (remote). Media server + Basic disk
-backup for remote A goes to MSDP then duplicate to B using schedule slp.
-There are backup that uses B1 as destination and there are also backup that uses B2 as destination as well
-All backup to disk eventually will destage to tape, this is hourly
-All SLP from remote site will replicate to B1 MSDP then duplicate to tape. I have schedule slp setup for this. Only runs during offpeak (non business hours)
As you can see, all backup eventually will write to tape. Because of destaging to tape AND duplication from MSDP to tape runs in serial, the tape drives will gets very busy and all jobs will be competing for it.
the problems:
1. as more destaging jobs and slp jobs competing for tape drive resources, we have to keep increasing our the disk size for backup. Backup images are not fast enough being dumped to tape causing bakcup to fail with disk storage is full.
2. we are already using job priority on backup jobs.the problem is, those high priority job will use the tape drive and keeping those low priority job queue, when next round backup comes in then writing to tape, it will goes into a queue. So this is kind a snow ball effect eventually, duplication jobs and destaging jobs gets more and more in the queue but little gets completed.
We have put mail, database,etc as high priority but they are also have large backup in size, hence it will take long to finish writing to tape (hogging the tape drives).
my questions:
1.from my observation, we are in need more of tape drives, but how many more? is there some sort of formula to calculate this (best practise some sort)
2.has anyone have similar environment and setup? what would be your solution or way around the tape drive bottle neck?
thank you everyone for your assistance.
True - it is best practice to NOT zone disk WWPN target and tape WWPN target to the same server/appliance initiator WWPN.
It also used to be best practice - for some older HBAs - to also not mix tape and disk on the same dual port HBA - but this is less and less true these days with more modern HBAs. So, most sites do now mix tape and disk on the same server side dual port HBA card, but just NOT on the same HBA port.
If your server has two dual port HBAs, and thus four initiator ports, and you have dual (resilient) fabric SAN design, then perhaps you can do this:
server HBA1 port 1 initiator - disk target - fabric A
server HBA1 port 2 initiator - tape target - fabric B
server HBA2 port 1 initiator - tape target - fabric A
server HBA2 port 2 initiator - disk target - fabric B
