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Rank: Newbie
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Joined: 10/15/2009
Posts: 2
Location: northampton, england
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I have 2 backup drives which I swap weekly incase one gets lost, damaged or stolen, when swapping drives do I need to run a full backup first every time or does Cobian recognise which files have been added/altered when using differential or incremental in the seven days that a different backup drive was connected.
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Rank: Advanced Member
Groups: Moderators
Joined: 12/21/2007
Posts: 965
Location: USA
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bdbland wrote:I have 2 backup drives which I swap weekly incase one gets lost, damaged or stolen, when swapping drives do I need to run a full backup first every time or does Cobian recognise which files have been added/altered when using differential or incremental in the seven days that a different backup drive was connected. You need to plan this out to meet your backup needs. Cobian generally does not look at what is on the destination to figure out what to do... the destination just needs to be there when Cobian needs to use it. If you are using Cobian to automatically cycle separated backups, the correct destination drive must be connected when Cobian needs to delete older stale backups on it. Cobain looks at the source files when deciding incr/diff backups. So, it will merrily continue placing these backups on the next swapped drive. The problem comes later... since you have spread a backup set (full and incr/diffs) across two devices, this set cannot be simply purged when required without you manually connecting drives and doing this... and fixing Cobian's History. So, this is not a good plan. I would confine full backup sets to one device... i.e. start a new device with a full backup. Backup device rotation such as tape rotation (or drive rotation) requires a pre-determined coordination method. Cobian is not yet built to do this... to track rotating media, so if you intend to setup a scheme like this, you will have to plan it out carefully, anticipating typical scenarios like forgeting to swap media, etc., and then maintain your scheme MANUALLY. First, I would learn how Cobian works. Me, I would keep it simple... a simple backup is better than no backup when everything is not perfectly executed. Glenn
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Rank: Newbie
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Joined: 11/21/2009
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I found this post and was planning on doing the same thing of using 2 drives. Here is what I'm planning; I'm hoping a more experienced user can tell me if it should work or not. I will do a full backup onto drive A which will clear the archive bit on all the files backed up. This is the master backup to which all subsequent ones will be referenced.
From this point on, all backups (until I decide to create a new master) will be with the "clear the archive bit" unchecked, so they will know about all modified files relative to the master. I will do a full backup onto drive B a week after doing the full backup to drive A, and then alternate A and B using differential backup until I decide to create a new master.
When I decide to create a new master I will do a full backup onto drive A with the "clear the archive bit" on and then repeat the process outlined above.
Thoughts and comments?
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Rank: Advanced Member
Groups: Moderators
Joined: 12/21/2007
Posts: 965
Location: USA
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mikemac wrote:I found this post and was planning on doing the same thing of using 2 drives. Here is what I'm planning; I'm hoping a more experienced user can tell me if it should work or not. I will do a full backup onto drive A which will clear the archive bit on all the files backed up. This is the master backup to which all subsequent ones will be referenced.
From this point on, all backups (until I decide to create a new master) will be with the "clear the archive bit" unchecked, so they will know about all modified files relative to the master. I will do a full backup onto drive B a week after doing the full backup to drive A, and then alternate A and B using differential backup until I decide to create a new master.
When I decide to create a new master I will do a full backup onto drive A with the "clear the archive bit" on and then repeat the process outlined above.
Thoughts and comments? Seems complicated and confusing to me. I would just make normal backup sets consisting of fulls and subsequent incrementals or differentials. I would allow Cobian to manage the archive attributes by clearing them when it should. I would scrap the master concept... a backup is a backup in time, period... the backup you want is the one that has the files you need to recover. The more backups over time you have, the better, subject to practical constraints. Glenn
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Rank: Newbie
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Joined: 10/15/2009
Posts: 2
Location: northampton, england
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Since my original question I have changed my methods, I now backup every day using a full backup. As it runs through the night while it's not slowing me down from doing other work it's not a problem and I can be confident of all my work being saved.
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Rank: Advanced Member
Groups: Moderators
Joined: 12/21/2007
Posts: 965
Location: USA
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bdbland wrote:Since my original question I have changed my methods, I now backup every day using a full backup. As it runs through the night while it's not slowing me down from doing other work it's not a problem and I can be confident of all my work being saved. A full backup consume more time and space. The more time a backup takes to complete, the more likely it will be interrupted and not completed. The more space consumed by one backup, the less space for holding additional backups, particularly the one that saved the version of the file you want to restore... the version that is not in your most recent backup. Glenn
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