3 reasons I don't like Storage Lifecycle Policies (in NetBackup)
At the beginning I have to admit that Storage Lifecycle Policy (SLP) is a great idea.
During ancient times of NBU we had NBU Vault available. Nifty tool allowing us to select backup images by various filters and create new copies on tapes prepared to eject from tape library and transport to offsite location. And by reading documentation for 7.6 version it supports duplication from any Storage Unit (STU) to any STU. (Do I remember properly some limitations in older versions?) But as I remember it requires explicit license - not cheap for non-capacity based NBU customers. The configuration allows you to duplicate anything but you have to do it properly to really get all images you need. My personal opinion is that simple script creating proper list of images (the though part) and then to run bpduplicate command can do the same. NBU Vault offers you nice GUI for configuration and some few more nifty features.
Since NBU version 7 the SLP was born. Put in basic installation, no special license required. Easy to use, easy to configure. Using the same bpduplicate command as backend. But there are big differences. The main one is that SLP is considered as logical backup destination unit and all backups using it will just follow some rules to get desired amount of backup copies on the right places. Other big difference is possibility to chain duplications and select which copy will be used by which duplication. Pretty nice if you need (e.g.) disk copy of backup in company remote branch, another short retention disk copy in headquarter, long retention tape copy and and offsite tape copy due to legal demand.The biggest difference visible to user/admin is simplicity! There is almost nothing to configure (and of course screw up).
As I mention already - great idea.
And now comes the list of reasons why it's not great implementation. It seems like it's designed by different bunch of people they never seen NBU Vault. Is the rumor about buying of some other SW product by Symantec right?
I wanted to start the list by impossibility to schedule time windows for duplication. Till I put this article handled in my head to paper the NBU7.6 arrived and this feature was added. I have seen discussion thread on Symantec Connect forum what feature should be included in new version of SLP. Symantec have chosen scheduling of SLPs as the most demanded feature.
What?!? Just one feature from the pretty huge list suggested by users?
- Limited support of STU for initial backup.
You can use just media based STU or dedup pool. We have to use few basic disk STUs for particular reasons with demand for offsite copy and we cannot use SLP. The basic disk STUs are just not listed in pull down menu in SLP configuration.
Why? What's the reason for it? SLP is using bpduplicate as backend and it doesn't care. Symantec had to explicitly code to filter out such STU in SLPs. Why? We are using manual duplication for such backups without any issues from GUI or command line. Why SLP cannot do it?
- Just global tuning parameters
You can tune SLP pretty fine. Minimum size of duplication job, force interval for small jobs and s.o. But they are just global parameters. No way to tune it on SLP level. I have SLPs where I have to create disk copy in other locality within 1 hour due to SLA. And there are SLPs where duplication can wait 1-2 days.
- Ignoring retention defined in schedule
This is my biggest reproach I blame SLP for. What's the reason? Why not to use retention defined in schedule for initial backup and then just to specify retention for duplication? The result is that we have to have configured tens of SLPs. Assume you have backups with various retentions but all of them have demand for the same offsite retention (usually given by law). I cannot create just one SLP for all these monthly backups. I have to create separate SLP for every retention required by initial backup.
Symantec, resolve these 3 issues above and I will consider SLP as best feature of NBU. I even had an idea to write it myself. Some nifty script will just run bppduplicate based on configuration file. Some combination of NBU Vault and SLP.
But as I have changed my job currently I have no idea whether I will meet NetBackup again.