* Number of CheckPoints
@ 2009-07-30 4:07 David Fuller
[not found] ` <4A711C80.1040500-ZE272gM1l1AAvxtiuMwx3w@public.gmane.org>
0 siblings, 1 reply; 3+ messages in thread
From: David Fuller @ 2009-07-30 4:07 UTC (permalink / raw)
To: users-JrjvKiOkagjYtjvyW6yDsg
Firstly thanks to Robertas for solving my initial problem with cleanerd
not running properly on Ubuntu 9.04 . Upgrading the nilfs tools worked
perfectly.
I was wondering how many checkpoints are kept and for how many days? I
see days worth of checkpoints going back about a week.
Regards,
--David F.
^ permalink raw reply [flat|nested] 3+ messages in thread[parent not found: <4A711C80.1040500-ZE272gM1l1AAvxtiuMwx3w@public.gmane.org>]
* Re: Number of CheckPoints [not found] ` <4A711C80.1040500-ZE272gM1l1AAvxtiuMwx3w@public.gmane.org> @ 2009-07-30 14:38 ` Ryusuke Konishi [not found] ` <20090730.233849.87826385.ryusuke-sG5X7nlA6pw@public.gmane.org> 0 siblings, 1 reply; 3+ messages in thread From: Ryusuke Konishi @ 2009-07-30 14:38 UTC (permalink / raw) To: users-JrjvKiOkagjYtjvyW6yDsg, dfuller-ZE272gM1l1AAvxtiuMwx3w Hi! On Wed, 29 Jul 2009 21:07:28 -0700, David Fuller wrote: > Firstly thanks to Robertas for solving my initial problem with cleanerd > not running properly on Ubuntu 9.04 . Upgrading the nilfs tools worked > perfectly. > I was wondering how many checkpoints are kept and for how many days? I > see days worth of checkpoints going back about a week. > > Regards, > --David F. At present, ``protection period'' is the only parameter determining the assured lifetime of checkpoints. You can extend or shrink it by changing /etc/nilfs_cleanerd.conf conffile, and you can store checkpoints up to the capacity of your drive. Note that a HUP signal must be sent to the cleanerd when you reflect changes on the conffile. Or you want to know the maximum number of checkpoints ? OK, here I show some calculation for your information: The maximum number of checkpoints (or snapshots) is, theoretically, 2 ^ 64 - 2 = 1.84467441 .. x 10 ^ 19 (about 18.4 exa checkpoints) In practice, maximum block count limitation will reach before this. For example, a 32-bit Linux kernel can handle up to 2 ^ 32 blocks. Since NILFS2 stores 21 checkpoints in a standard 4KB block, 32-bit nilfs can handle up to 90,194,313,215 (= about 90.2 giga) checkpoints If we create a checkpoint per 5 seconds, it corresponds to 18,038,862,643 seconds = 5,010,795 days = 13,728 years So the conclusion is, you know, up to the capacity of your drive ;) Cheers, Ryusuke Konishi ^ permalink raw reply [flat|nested] 3+ messages in thread
[parent not found: <20090730.233849.87826385.ryusuke-sG5X7nlA6pw@public.gmane.org>]
* Re: Number of CheckPoints [not found] ` <20090730.233849.87826385.ryusuke-sG5X7nlA6pw@public.gmane.org> @ 2009-07-30 14:52 ` Ryusuke Konishi 0 siblings, 0 replies; 3+ messages in thread From: Ryusuke Konishi @ 2009-07-30 14:52 UTC (permalink / raw) To: users-JrjvKiOkagjYtjvyW6yDsg, dfuller-ZE272gM1l1AAvxtiuMwx3w On Thu, 30 Jul 2009 23:38:49 +0900 (JST), Ryusuke Konishi wrote: > For example, a 32-bit Linux kernel can handle up to 2 ^ 32 blocks. > Since NILFS2 stores 21 checkpoints in a standard 4KB block, 32-bit > nilfs can handle up to > > 90,194,313,215 (= about 90.2 giga) checkpoints > > If we create a checkpoint per 5 seconds, it corresponds to > > 18,038,862,643 seconds = 5,010,795 days = 13,728 years > > So the conclusion is, you know, up to the capacity of your drive ;) I made a miscalculation. 90,194,313,215 checkpoints = 450,971,566,080 seconds = 125,269,879 days = 343,205 years. In either case, the conclustion is the same. Ryusuke ^ permalink raw reply [flat|nested] 3+ messages in thread
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2009-07-30 4:07 Number of CheckPoints David Fuller
[not found] ` <4A711C80.1040500-ZE272gM1l1AAvxtiuMwx3w@public.gmane.org>
2009-07-30 14:38 ` Ryusuke Konishi
[not found] ` <20090730.233849.87826385.ryusuke-sG5X7nlA6pw@public.gmane.org>
2009-07-30 14:52 ` Ryusuke Konishi
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