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BACK Up sequencing - any comments or advice?

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by limmartin 2 views

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Our schedule, any comments?
we have been doing this...

1st back up full (anyday)
mon-thu differential
fri full
Month end full (last friday of the month)

We have 2 sets mon-fri tapes, 1 for odd month and the other for even month.

As for month end, we retain 12 tapes (one for each month).

Any comments on this? Please share your experience and advice what I can do to improve..thanks in advance.

16 replies

by deadly ernest

Many places now use removable hard drives or a VPN data transfer to hard drives at another site.

The frequency seems right for most businesses, some with a high daily data input would increase the frequency of the differential (sometimes called incremental) to twice or three or four times a day, based on the business needs level of activity.

Also include in the operating procedures the need to check the back up tape did back up properly immediately it's made. being a worry wart I'd have four sets of the the mon-fri tapes so they rotate once a month, and maybe even two full sets of everything stored in two locations if the business is big.

Don't forget to schedule a reload from backup test every few months, even if it's only on a test bed set up. You'd be surprised how many businesses find out the hard way the back up reload system doesn't work or the backup media is faulty.

One story I heard of was a company that did regular daily and weekly backups but all the back up tapes were useless because the IT manager took them home to store in a secure safe kept in his house, all approved by the management. The company was in Chicago and he was from a warmer climate. the problem was the tapes were placed on the seat beside him each day, and the built in electric seat warmer in his fancy car was on all the time as he was too lazy to turn it off; never enough to wipe the tapes, but enough current to mess them up good. look for the b u g g e r factor in the operational set up and account for it.

by charliespencer

'Differential' and 'incremental' are not interchangeable terms.

Differential backups back up everything that has changed since the last full backup.

Incrementals backup everything that has changed since the last full backup OR the last incremental.

Day 1 - Files 1, 2, and 3 change.
Differential - backs up 1, 2, and 3.
Incremental - backs up 1, 2, and 3.

Day 2 - Files 2 and 4 change.
D - backs up 1, 2, 3, and 4.
I - backs up 2, and 4

The advantage of incrementals is that in a high transaction volume environment, they require much less time and backup media. The disadvantage is that they take much longer in a full restoration situation, since all the tapes must be used.

by deadly ernest

they used tapes they had the terms as being totally interchangeable as a rebuild after a crash on say Thursday required the last full backup, add the Monday tape, add the Tuesday tape, add the Wednesday tape to get to Thursday morning. The incremental approach.

From what you say a differential rebuild would be the last full back up plus Wednesday's tape as it would include the Monday and Tuesday changes. I can see that's more effective but would take longer and need less tapes.

Most places I worked where I was in the area that did the back ups we had routines that did VPN backups to servers at other locations as the organisation had multiple computer sites around the country, so everyone backed up to everyone. That way we only ever needed on of the six systems to survive to be fully operational. Sure it used disc space, but that was much cheaper than a major crash downtime was.

by charliespencer

Apparently my explanation was clear (for once). That's exactly how differentials work. All you need to restore is the last full and the most recent diff. Yes, each diff takes longer to run than the previous ones.

by limmartin

Hi Palmetto and Ernest.

Thanks for the insights on DIff and Incremental.

A current project customer has only 1 office. In 3 years their DATA grew to 35GB.
We are looking at getting Storageworks DAT72x10 autoloader. I thought that was a little exagerrated but the owner wants it to be fully automated. What do you say to this? I guess with the autoloader, we can use the diff approach more seamlessly. any thoughts? thanks in advance.

by deadly ernest

looked at an auto-loading DVD burner to burn the data to and just put them all in storage like that. That would be an on-going expense of about fifty cents to a dollar per disc depending upon the bulk buy quantity. I know someone who set that up with CDs many years ago as they had an auto loading CD burner, bought to do commercial copying of the software they sold - small company. They just used another program to run their data backups with the same hardware. Load, burn, eject - load, burn the next lot, eject - repeat.

by limmartin

thought I'd post it here since we're in the topic of back up.

Grandfather, Father, Son (GFS) rotation method
has always worked for me. You can use 12 tapes at a minimum but 20 would be recommended as the end of month backup will extend your data retrieval options.
Posted: 08/24/2009 @ 01:12 AM (PDT)
Jacky Howe 866
Job Role: Technical/PC Support
Location: Bundaberg, Queensland
Member since: 08/21/2002

by charliespencer

I never worked with an autoloader. I was going to leave this question alone until you deferred to me. My monthly complete b/u's take three tapes, but they finish in a normal work day. Even at the end of the monthly cycle my diffs will still fit on a single tape.

That said, for any b/u solution consider the cost of the media. Some businesses (financial, medical, legal, etc.) are required to store each monthly set off site permanently. That's money going out the door that isn't coming back. Keep in mind how much your annual media expenditures are going to run.

by maclovin

Daily (Incremental)- MON-THU
FULL (Recycle/New Media) - FRIDAY

I rotate the full tapes every three weeks.

They're not put into my car with a fancy seat heater(...though I have one, it's not that fancy...a 95 Saab 900.).

The Full tapes go directly to the bank on Monday/Tuesday. The daily one stays in the server room.

by charliespencer

My monthly full set goes to the house. Each nightly differential goes to the house, and I bring back the previous day's diff in the morning. At the end of the month, the last full set is replaced by the new one. The older full set comes back and gets shipped to our other facility; they transfer it to permanent off-site storage.

by maclovin

...still recycles the past media every month then, if I understand correctly.

Which is what I was thinking of doing, as I never understood why my predecessor chose every 3 weeks...lunacy I guess :D

by limmartin

it beats buying autoloaders! any idea what the software name is? I guess you'd have to get a tower type casing and build a machine running on XP or Server and install that software to act as an autoloader. Right?

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