Discussions related to exporting backups to tape and backing up directly to tape.
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redhorse
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Media set and retention

Post by redhorse »

Hello,

how does it exactly work with media set, retention and media pool? So, here is what I do:

- Create one media pool with one week retention and create a new media set once a week (short before a Virtual Synthesized Full Backup to tape runs)
- Create one Backup-to-Tape and one File-to-Tape Job with processing fulls and incrementals into this media pool

So that means:

- Saturday: Virtual Synthesized Full Backup + File-to-Tape (Media set 1)
- Sunday: Incrementals + File-to-Tape (Media set 1)
- Monday Incrementals + File-to-Tape (Media set 1)
- Tuesday: Incrementals + File-to-Tape (Media set 1)
- Wedesday: Incrementals + File-to-Tape (Media set 1)
- Thursday: Incrementals + File-to-Tape (Media set 1)
- Friday: Incrementals + File-to-Tape (Media set 1)

- Saturday: Virtual Synthesized Full Backup + File-to-Tape (Media set 2)
- Sunday: Incrementals + File-to-Tape (Media set 2)
- Monday Incrementals + File-to-Tape (Media set 2)
- Tuesday: Incrementals + File-to-Tape (Media set 2)
- Wedesday: Incrementals + File-to-Tape (Media set 2)
- Thursday: Incrementals + File-to-Tape (Media set 2)
- Friday: Incrementals + File-to-Tape (Media set 2)

When are which tapes free to overwrite? I think, when using one week retention, all tapes of one media set should be protected for one week after the backup on Friday, is that correct?
PTide
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Re: Media set and retention

Post by PTide »

Hi,
When are which tapes free to overwrite? I think, when using one week retention, all tapes of one media set should be protected for one week after the backup on Friday, is that correct?
Correct. When the data protection period is over the oldest tape from the media set will be the first in the "Overwrite" queue.

Thank you.
redhorse
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Re: Media set and retention

Post by redhorse »

PTide wrote:Correct. When the data protection period is over the oldest tape from the media set will be the first in the "Overwrite" queue.
Hmmm.... after the first backup I have three tapes in the first media set, tape one and two have the same expiration, but the last tape which consists also the file-backup has a later expiration. Is that correct? What will happen when the next increments are stored on this tape and on new tapes?
PTide
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Re: Media set and retention

Post by PTide »

but the last tape which consists also the file-backup has a later expiration. Is that correct?
Correct.
What will happen when the next increments are stored on this tape and on new tapes?
I'm not sure what you mean. If a tape contains several backup sets, it will expire when the backup set with the longest retention period expires. Does that answer your question?
redhorse
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Re: Media set and retention

Post by redhorse »

PTide wrote:I'm not sure what you mean. If a tape contains several backup sets, it will expire when the backup set with the longest retention period expires. Does that answer your question?
Perhaps I explain what I want to achieve:

I want to be sure that a whole backup set (which is the full backup of saturday + 6 following increments) is protected for one week. I move the tape out of the library every day so what I understood is that there will be created a new media set with each backup. When I set the retention for one week I fear that the tape with full backup will be deleted after one week and the other tapes with increments become useless.
PTide
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Re: Media set and retention

Post by PTide »

I move the tape out of the library every day so what I understood is that there will be created a new media set with each backup.
New media sets are created in accordance with your media set policy. As you've mentioned in your OP a new media set is created once a week.
fear that the tape with full backup will be deleted after one week and the other tapes with increments become useless.
Ok, now I see what you mean. Assume that you're out of free tapes and the protection period of the first tape containing full backup has just expired. In this case the tape will be overwritten, rendering the whole chain of subsequent incrementals unusable. The possible workaround is to use separate media pools for Full and incremental backups or trigger Tape Protection via PowerShell.

Thank you.
redhorse
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Re: Media set and retention

Post by redhorse »

PTide wrote:New media sets are created in accordance with your media set policy. As you've mentioned in your OP a new media set is created once a week.
But they are also created when there is no tape to append, is that right? What I thought is that all tapes in a media set have the same expiration, but that's wrong, isn't it?
Ok, now I see what you mean. Assume that you're out of free tapes and the protection period of the first tape containing full backup has just expired. In this case the tape will be overwritten, rendering the whole chain of subsequent incrementals unusable. The possible workaround is to use separate media pools for Full and incremental backups
Okay, I understand that way. So there is no mechanism to have a retention for full backups and incrementals like "I need restore points for two weeks"? In case of using two media pools I will have tapes with useless restore points which are still protected.
veremin
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Re: Media set and retention

Post by veremin »

But they are also created when there is no tape to append, is that right?
Could elaborate on that? You're asking whether a new mediaset gets created, when a tape job uses a new media, right?
Okay, I understand that way. So there is no mechanism to have a retention for full backups and incrementals like "I need restore points for two weeks"?
For how long should the data stored on tapes be preserved? Week it's been written to and the week after? If so, just set 2 weeks as a protection period. Thanks.
redhorse
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Re: Media set and retention

Post by redhorse »

v.Eremin wrote:Could elaborate on that? You're asking whether a new mediaset gets created, when a tape job uses a new media, right?
Yes, in my case I release the tape every morning. So it will be created a new media set every day, am I right?
For how long should the data stored on tapes be preserved? Week it's been written to and the week after? If so, just set 2 weeks as a protection period. Thanks.
Yes, your example is fine. But it just works when I have one continous mediaset for each week because with every new media set a new retention period is beginning. That's right?
Shestakov
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Re: Media set and retention

Post by Shestakov »

redhorse wrote:Yes, in my case I release the tape every morning. So it will be created a new media set every day, am I right?
Correct.
redhorse wrote:Yes, your example is fine. But it just works when I have one continous mediaset for each week because with every new media set a new retention period is beginning. That's right?
What Vladimir meant is if you create a new media set every day and you want the first media set to be protected one week after the 7th media set is created, you need to set an option to protect media sets for 2 weeks.
And yes, every new media set has its own expiration date, but the protection length is same(2 weeks in our case).
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