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Here's my scenario: I have two servers (well many more, but two for this scenario), one is a Solaris backup server, the second is a CentOS Linux Server. Every night the CentOS server runs a cron job to rsync itself to the Solaris backup server. After this is done, it puts the date and time into a special file on the Solaris server. The Solaris server has a cron job run every minute and if it sees this file, it grabs the contents and uses that to make a snapshot.

The result is great: Every day the backup automatically runs and then creates a ZFS snapshot. Been working great for over two months. I had expected that by now I would be low on space and would need to start (manually) deleting old snapshots. But in fact, I am fine on space. My only concern is, with 60+ snapshots and more being added daily, are there any known problems with large numbers of ZFS snapshots? Is there a maximum number of ZFS snapshots a ZFS filesystem can have? Or am I OK to just keep accumulating snapshots until I am low on space?

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2 Answers 2

up vote 5 down vote accepted

There's no problem with lots of snapshots. Having thousands of ZFS filesystems can cause boot times of more than an hour, but you're not doing that.

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Awesome, thanks! I accepted your answer because of the link. –  Josh Oct 23 '09 at 15:28
    
unfortunately oracle have helpfully broken all their links so this answer is not very useful anymore –  JamesRyan Jun 5 '13 at 10:31
    
@JamesRyan Fortunately the internet archive saved a copy, so I've updated the link in my answer. –  TRS-80 Jul 4 '13 at 6:16
    
What do you think of creating a snapshot on every file change? Disregard temporary files or stuff in RAMFS/TMPFS. –  CMCDragonkai Jun 27 at 3:05

I wouldn't be too concerned about this. You're talking about 1 snapshot a day here. I have heard of production environments with over 10k snapshots. But I don't have any information on how this was working for them but I didn't hear it in a bad context so I'm going to assume that it was working well.

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Thanks a lot! I wish I could have accepted both your answer as well as TRS-80's answer... But your was almost equally as helpful! –  Josh Oct 23 '09 at 15:28

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