Re: [Veritas-bu] How to properly calculate the Catalog

Todd,

That formula in the manual is completely worthless. I can’t believe they still publish it. The SIZE of the data you’re backing up has NOTHING to do with the size of the index. What matters is the number of files or objects.

I could backup a 200 TB database with a smaller NBU catalog than you’ll have with your files. To get the real size of the index:

Calculate number of files/objects in your entire dataset (N)
Calculate number of files/objects that changes on a daily basis (I)
Calculate how many “cycles” you’ll store (sets of fulls and incrementals) (C)

Assuming weekly fulls and daily incrementals and keeping 12 weeks:

(N + (I x 6)) x 12) = Number of objects tracked in the index

Multiply that times 200 bytes or so and you have your index size.

(I say 200 bytes or so. The actual number is based on the average length of your files’ path names. 200 is actually large and should over-estimate.)

From: veritas-bu-bounces AT mailman.eng.auburn DOT edu [mailto:veritas-bu-bounces AT mailman.eng.auburn DOT edu] On Behalf Of Todd Jackxon
Sent: Friday, March 13, 2009 8:41 AM
To: veritas-bu AT mailman.eng.auburn DOT edu
Subject: [Veritas-bu] How to properly calculate the Catalog

Hello All,

I am trying to use the formula for calculating the catalog and not sure about the results. Has anyone
Calculated the catalog using the formula in the Performance Tuning guide?
Can you please explain how to properly do this?

1 – "When the formula states total backups" ... is this for one Full backup of all data for one day?

Schedule

Incremental - daily - retention 5 weeks
Weekend Full - retention 6 weeks (only first 3 weekends)
Month-End - retention 1 year (last Saturday of the month)

Below is my attempt to calculate this. Any clarification would be appreciated.

-----------------

614GB data back up   * 3 Full Backups (1842GB) * 2 months retention (3684GB) = 3.5 TB
Full

447GB data back up   * 1 Full Monthly Backup (447GB) * 12 months retention (5364GB) = 5.2 TB
Month End Full

122GB
incremental * 30 incr backups monthly (3660GB) * 5 week retention (1.25 months) 4605GB = 3.5 TB
--------------

3.5 TB incr
3.5 TB Weekly Full
5.2 TB Month-End Full

= 12.2 TB = Netbackup catalog size (2%) = 240GB Catalog space

This does not seem right???

Thanks
Jack

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