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Avamar Frequently Asked Questions

Q. I recently deleted a lot of backups. How do I tell how much space I will get back?

A. You can get a rough estimate how much space will be reclaimed when a specific backup

is deleted by running a DPN Summary report. Below is an excerpt from an "Ask the Expert"

session on Avamar Server Management Best Practices that describes how to use DPN

Summary:

DPN Summary

There is a report built into the Avamar software called "Activities - DPN

Summary". This report will tell you on a backup-by-backup basis how much

new data is being sent to the server by a client.

To generate the report on your own Avamar system:

1. Open the Avamar Adminstrator GUI and log into the grid

2. Select Tools => Manage Reports...

3. Scroll down until you find "Activities - DPN Summary" and select it

4. Click the Run button

5. Select the appropriate date range (be aware that very large ranges could cause the GUI

to stop responding for some time) and then click Retrieve

6. Click the Export button and you can save the report as a file in comma separated values

(CSV) format so it can be imported into spreadsheet software for easier analysis

The columns that are likely to be of most interest will be columns I (as in

India) through M (as in Mike). These columns are, respectively:

I - ModReduced - Bytes saved by using compression

J - ModNotSent - Bytes present on the Avamar server but not in the client

caches

K - ModSent - New bytes added to the server by the backup

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Avamar Frequently Asked Questions

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L - TotalBytes - The total size of the data being protected (whether or not we

had to send it)

M - PcntCommon - The percentage of data for the backup that is already on

the grid (higher is better)

Column K in particular is useful for measuring capacity and capacity growth.

Using the ModSent information for each backup still present on the grid and

the size of the initial backup for the client, you can do a rough "back of the

envelope" calculation of how much space that client is consuming on the

grid.

One quick caveat - the DPN Summary is a report, not a status which means

it includes information for backups that may have already expired from the

grid.

Q. How can I tell how much expired data is on the system waiting to be garbage

collected?

A. Unfortunately, due to an architectural limitation, it is not currently practical to report on

exactly how much expired data is on the system. Most of the time required for garbage

collection is spent calculating what chunks are eligible for removal and very little time is

spent actually removing the data. By the time the system calculates what is eligible to be

removed, it might as well just remove it.