Forum OpenACS Q&A: OT: Backup solutions

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1: OT: Backup solutions
Posted by Malte Sussdorff on 03/04/03 07:12 AM
I was wondering what you use for backups in your organization. At the moment we backup all our data to a dedicated backup server and plan to mirror that twice a week to another backup server in a different data center.

Now one of our clients asked us to investigate into a tape solution as well. I had my experience with ADR tapes which was fairly successfull, and I'd think about trying ADR2 out. The benefit seems to be high storage capacity (120GB uncompressed with two tapes) with high throughput (8MBit/sec data throughput). http://www.onstreamdata.com/products/adr2_240Sr.shtml has more details on that one.

OTOH I did not follow the development of tape driven backup solutions or other means of storing backups of your data lately, so I'm interested in how you do things.

In case you wonder, we use rsync for keeping the files in sync and rman as well as exp for the Oracle dumps. Talking about EXP. Never rely on it. Use rman (recovery manager).

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2: Re: OT: Backup solutions (response to 1)
Posted by Brad Duell on 03/04/03 04:28 PM
I use ADR (the Onstream ADR50e), and haven't found a reason (or been forced yet) to move away from it.

I've also found the server/client software from Arkeia, http://www.arkeia.com/, to be very reliable and user friendly (there's a nice section on their website for hotbackups - http://www.arkeia.com/hotbackup.html).

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3: Re: OT: Backup solutions (response to 1)
Posted by Jun Yamog on 03/04/03 05:50 PM
Just ssh, tar, pipe, pg_dump, bash and email.  Legs for offsite.  A tape drive or autoloader.  Primitive, but it does work :)

Also worked for a financial institution, commercial backup systems and autoloader.  There is also something for oracle that does batch jobs and some predefined decision making what and how to backup the oracle db.

DLT are good, but SLR are cheap and big on capacity.

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4: Re: Why never rely on EXP? (response to 1)
Posted by Roger Williams on 07/29/03 11:25 PM
Hello Malte:

In the first posting on this thread you say: Never rely on EXP. Can you elaborate? We have been using EXP for some months (although our export files is only 300MB) and it always seems to restore OK (so far).

TIA.

Regards..

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5: Re: OT: Backup solutions (response to 1)
Posted by Mark Aufflick on 07/30/03 08:34 AM
Also I have to disagree with Jun that DLT are good...

DLT is an amazingly old technology that is expensive, inconvenient, and finicky.

For instance, the tension on a wound tape is critical - if you drop a cartridge and the tension is sufficiently stuffed, you can actually break your DRIVE.

Also, it can be very slow for network backups if you can't stream data fast enough for the tape. The tape speed is so high (due to it being linear) that every glitch in your data makes the tape have to slow down, overshoot, rewind back past the point far enough so it has enough distance to get up to speed, then get going again. That said, big buffers help a lot.

Plus the media is rediculously expensive.

My preference is to use AIT drives http://www.aittape.com/ - not only is the memory chip cool, but it is awesome for random access and tape loaders - if your software supports it.

Of course DB backups/restores don't really need all that much random access...

I have heard good things about exabyte mammoth drives http://www.exabyte.com/, and they have cheaper drives and media than ait - but I have never tried them myself.

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6: Re: Why never rely on EXP? (response to 4)
Posted by Dirk Gomez on 07/30/03 09:54 AM

Roger, when you export your database, you cannot have point-in-time recovery in case of a media failure.

You will lose all changes since your last backup. You cannot re-apply the data in the archived redo logs because with an import, your old rowids will get lost. And Oracle keeps book about changes in the redo logs via the rowids.

Also if you search metalink, you'll find a lot of issues with full database exports. I hope you are doing a schema export?

And last but not least: exp and Intermedia don't play together.

exp should be part of your backup strategy nonetheless, because it provides backups on a logical and consistent level.

Depending on your uptime requirements and how dear your data is to you, you might shutdown your database every night and take a cold backup. Otherwise you must look into taking hot backups.

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7: Re: OT: Backup solutions (response to 1)
Posted by Jun Yamog on 07/30/03 12:15 PM
Hi,

Anyone tried using MiniDV for backup?  :)  13GB and you have a camcorder as your backup device.  Nice nifty personal backup.

Anyway can anyone elaborate more of the different Oracle hot backup's done in OACS?  Using in their production systems.

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8: Re: OT: Backup solutions (response to 7)
Posted by Andrew Piskorski on 07/30/03 02:49 PM
It's been discussed here before.

Currently I both do an export and an rman hotbackup every night, although some of the larger (data warehouse type stuff) tablespaces I may only export once per week, if the server they're on is old and slow. The export and hotbackup files then go to tape.

I've tweaked those scripts I posted them a year, but they do basically the same thing. The script are also a bit baroque in places (the various options and redirection of output and such), but that seemed useful when I was testing them.