[opensuse] Re: btrfs qgroup / quotas concerns - revisited

Richard Brown wrote:

On 3 January 2017 at 10:45, nicholas wrote:

...

...

They are enabled in order to facilitate the "Cleanup based on Disk Usage" feature in snapper - http://snapper.io/2016/05/18/space-aware-cleanup.html

Considering "snapper made too many snapshots and filled up my hard disk" is by far the #1 complaint from openSUSE users from the last few years, I would say that the features required to mitigate or remove this problem are most certainly required to be on by default on a user system.

and that would be good but TW default SPACE_LIMIT is set at 50%!

What's wrong with that? Available Free space isn't doing anything. Using 50% of the available free space seems like a very sensible default.

---- Not entirely. If free space < 25%, it should stop keeping snapshots -- OR, it should allocate some fixed percentage of overall disk space when it is initialized -- like MS's ability to tune the amount of space for snapshots -- defaulting to ~10% or so. If you have it dynamically using 50% of the free space, how will it respond if a user goes from 25% usage to 75% usage on their disk in one day (they created a several VM's maybe). If the space used by the snaps is contig, then not so much of a problem, but if it constantly shrinks and extends leaving fragments in the remaining free space, it will eventually hurt performance on large writes as well as overall read speed as free space becomes more and more fragmented over time.

...

over-the-top suse defaults have created and urban legend around the excesses of snapper. and all to achieve what in the typical use case?

An openSUSE system running snapper that works today is almost guaranteed that it can also work tomorrow, because of the certainty that you can rollback to todays state in the event of changes that break it.

---- Such is not true on MS's snapshot system. How can it be guaranteed on suse's? -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org