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MSDP /Storage/databases Symbolic Link Anyone?

Created: 01 Oct 2013 • Updated: 02 Oct 2013 | 3 comments
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Hi All,

I have noticed a very bad piece of programming in the PureDisk/MSDP code, the inability to move the databases filesystem/folder/partition from one mount point to another. I reference this post.

The dedupe guide warns against bad planning (agree muchly with this) but sometimes certain things are just out of your control, for instance, we were under severe pressure to get a system working (temporarily) for a customer, with limited time and limited resources we had to place the /Storage/databases under one LUN with the /Storage partition, eventually this started resulting in bad performance due to .tlogs growing into the hundreds of millions, I had noticed we needed to move the databases to another LUN/Disk/Location for improved performance, UNFORTUNATELY we hit a brick wall with lots of advice and posts on HOW NOT to move a databases directory, so as they say in Sunny South Africa, a boer maak a plan (A farmer, makes a plan). So we did that, we got hold of some super fast disk and created a symbolic link to the new location, moved all the files into the new location. Started the Netbackup services and voila, it works better than expected. This is but a temporary solution and I am sure it is frowned upon and wholly unsupported by Symantec BUT, it works and i just thought i would share my experiences with this. 

Symantec, would you care to elaborate on such poor coding/methodology behind this? Your MSDP/PureDisk solution uses a hacked/modified version of PostgreSQL and under a normal PostgreSQL installation I can move Databases and their locations around no problem by editing some config files, why can I not do this with MSDP? Or perform pgdump of my very important MSDP databases and instead use other weird proprietary methods to get it done?

Thank you all for reading yes

Operating Systems:

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mph999's picture

It can be moved.

How to relocate the Media Server Deduplication Database to another location on Linux - Tech TECH210407
The TN is 'Internal' and so I cannot post it up here, however, if you wish to use the procedure you are welcome to log a call and quote the TN mentioned above.
I cannot comment on why things are as they are - the detils such as you have understandable inquired about are almost certainly going to be 'Symantec' confidential I'm afraid.
However, I hope my contribution above will go some way to puting things right for you.
Regards,  Martin
Setting Logs in NetBackup:
watsons's picture

I agree with what you said. Have always been cautious about this Netbackup deduplication technology, when it was first introduced we did some tests to evaluate the feature, it's great in some aspects but it's not-for-all (or everyone).

I always tell my customer what is more important is their data, not the product feature. So having a great feature does not mean you have to risk all your data into it. The only data that is good for deduplication is your repeating data (that does not get changed over a period time). So when you want to implement deduplication, choose those repeating data. Analyze your data and selectively use deduplication for those you want - not ALL of them. Yes, you might not get some nice-to-have feature such as Auto Image Replication or Optimized duplication, but if it's not saving you significant diskspace or time, do not use it without first covering all the DR strategy. A lot of alternatives are out there.

Don't think Symantec will provide the deduplication engine design as it's kind of an IP, but I guess it will be improving over time. That said, I still love using Netbackup, just not all their (new) features. 

NetRestore's picture

Mph999, thank you... Much appreciated for shedding some light on this.