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On Wednesday 28 May 2014 13:07:49 Alan McKinnon wrote: |
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> On 28/05/2014 11:58, Joost Roeleveld wrote: |
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> > On Tuesday 27 May 2014 23:35:26 Alan McKinnon wrote: |
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> >> On 27/05/2014 17:12, J. Roeleveld wrote: |
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> >>> I have a yearly (full), monthly, weekly and daily. Each incremental is |
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> >>> against the most recent one of itself or longer period. |
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> >>> That means having to keep multiple snapshots active, which I prefer to |
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> >>> avoid. |
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> >>> |
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> >>> But, it is a good idea for backing up desktops and laptops. |
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> >> |
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> >> I'm curious why you have yearly snapshots. I've yet to find any sane |
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> >> production system where a yearly backup had any worth at all. Even |
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> >> monthly is pushing it... |
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> >> |
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> >> Or do you do it to have a decent start point for incrementals? |
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> > |
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> > It's to have a decent start point for incrementals. |
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> > Below are the 2 biggest shares on the NAS: |
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> > |
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> > /dev/xvda17 7.1T 5.9T 1.2T 84% /data/unsorted |
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> > /dev/xvda16 3.0T 2.4T 517G 83% /data/software |
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> > |
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> > It is impossible to do a full backup on a daily or even weekly basis. |
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> > |
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> > Previously, I had 1 full backup and then a daily incremental. This appears |
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> > like a good idea, untill you need to restore the filesystem from backups |
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> > when the crash occured 2 years later. |
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> > That is 1 full backup and over 700 incrementals.... |
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> > |
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> > Currently, I do the following: |
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> > Every year, a full backup |
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> > Then, every month, I have an incremental based on either the yearly or |
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> > previous monthly. |
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> > Ditto for the weekly (but then based on monthly or weekly) |
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> > And again for the daily. |
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> |
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> OK, that makes sense. |
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> |
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> It reminds me of an issue my wife had with the data warehouse when she |
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> worked at the bank. In a nutshell, they needed backups but backups were |
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> impossible to achieve because physics says so. They needed to get data |
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> off the disk 4 times faster than data comes off a disk - SCSI limits |
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> being rather hard limits :-) That opinion didn't go down well when I |
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> offered it |
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Haha :) |
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I know the feeling. |
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I'd love to know the final solution they came up with. |
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|
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> The solution was to do it much like your plan above. |
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> With the benefit that the infrequent full backups would be done on a |
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> fixed schedule in a change window with X hours downtime that was known |
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> well in advance. |
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Using snapshots, the downtime is the same couple of minutes each night. |
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The problem is that during the backup, the performance of the server is |
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impacted. For a full backup, that means weeks... |
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-- |
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Joost |
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