So over the weekend we had to rebuild a customers Domino server. While we were at it we enabled DAOS on it.

Prior to DAOS, 90%+ of the mail already had the 8.0.1 compression enabled so any gains there were negligible. Below are the bullet points:
  • The total size of the mail files prior to DAOS was 146GB.
  • The conversion took just under 4 hours an a Dell 2900 with dual core 3.0 GHz Xeon, 2GB RAM, 32 bit OS and Domino
  • After DAOS the mail file size was 5.63GB and the DAOS folder was 27.0GB, for a combined total of 32.63GB

By my calculations that is 77% reduction is disk space.

DAOS continues to amaze me.
Darren Duke   |   March 2 2009 07:30:00 AM   |    domino  daos  8.5    |  
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Comments (7)

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1 - Jon Harris       03/10/2009 1:45:38 PM

Everyone tends to leave out the little snippet of how much Transactional logging factors into the setup for DAOS.. I guess because everyone assumes most people are just running anyway, DAOS or no DAOS. We however are not, so could you tell us what their trans logging config was and how much disk they had dedicated to it?

If you were to assume a site didn't have trans logging configured, how does that change your percentage when you factor in how much disk is assigned?

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2 - Darren Duke    03/10/2009 1:47:31 PM

Apparently I am popular today at ;)

And I love the fact your web site is in Domino, way to go! Anyway back to the question at hand.....

This particular customer has circular tx logs with a 4GB limit. The logs were stored on the same drive as Domino (--*Eck but that is not supported*--) and it runs fine. YMMV.

I'll see if I can make sense of the transaction log settings. Basically the logs are written to the drive and folder specified in the server doc. Each log file is 64MB in size and Domino pre-creates these. There are several types of logging:

1) Circular logging and this has a maximum disk footprint of 4GB (4096MB). Unless you need point in time restores of NSF files then this is the way to go.

2) Archiving logging is a bit like circular except without the limit. This is required for point in time restores. Each time the tx log is backed up (i.e. the archive flag is set) it can be reused by Domino again.

3) Linear is a bit of a mystery to me. Never used it.

For a 4GB maximum for circular it seems a shame to waste an expensive 250GB SAS drive ;)

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3 - Darren Duke    03/10/2009 2:05:33 PM

Whoops missed the last question and a good one it is too:

As this client used a fixed 4GB tx log size then that would make the combined total equal to:

5.63GB (nsf) + 27.0GB (DAOS folder) + 4GB (tx logs) = 36.63GB

This is still a substantial saving is disk space, somewhere in the region of 75%. Not too shabby.

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4 - Marc Resnick    03/11/2009 8:03:58 AM

My understanding is that DAOS does not work on local replicas. If true, it makes sense. I am cogitating, however, on ways to harvest the power of DAOS to benefit local replicas. I have many customers who would definitely benefit.

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5 - Chad DeMeyers    03/13/2009 3:43:51 PM

Linear logging is like circular logging, except it allows more than 4GB. Use linear logging if the size of the log needed between full database backup intervals is greater than 4GB, and you are not using archive media.

Here is the full description from the Notes 8 admin help file...

There are three logging styles to choose from -- circular, linear, and archived. The logging style you choose is also dependent on your disk size and backup strategy.

With circular logging, Domino reuses a fixed amount of disk space (up to 4GB) for transaction logs. After the disk space is used up, Domino starts overwriting old transactions, starting with the oldest. When the space fills up, perform a backup on the databases. You may need to do daily backups to capture database changes before they are overwritten, depending on the server activity level. Use circular logging if the size of the log needed between full database backup intervals is less than 4GB.

Linear logging is like circular logging, except it allows more than 4GB. Use linear logging if the size of the log needed between full database backup intervals is greater than 4GB, and you are not using archive media.

Archived logging creates log files as needed. It simplifies backup and restoration, and provides online and partial backups. The log files are not overwritten until you archive them. With archived logging, you must have a backup utility to back up the filled log extents so that they are ready if needed. If you do not have a backup utility, the server continues to create log extents, fills up the disk space, and then panics.

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6 - Chandrasekhar Chinni       03/03/2010 5:22:40 AM

there exists some of the issues.

As i understood DAOS folder can not be moved phyisically to any other server / location.

This worries to consider the DR scenario's or hardware migrations.

Need to get some answers clarified around this yet from IBM.

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7 - Darren Duke    03/03/2010 7:19:47 AM

By default the DAOS repository IS ENCRYPTED WITH THE SERVER ID. This means that the DAOS repository can only be moved to new hardware (or restored from backup) to the same server ID file. You can turn this encryption off with a server notes.ini file setting, but I, as a general rule, I prefer security offered by this encryption. So also make sure to backup your server ID files ;)

Should DAOS be encrypted (and why wouldn't you?) then you CAN NO LONGER JUST COPY NSF FILES TO OTHER SERVERS. The fact that this is not supported nor recommended by IBM notwithstanding, there are other benefits to replicating the NSF files to a new server over an OS level copy.