On 10/2/18 9:37 AM, Emmanuel Florac wrote: > Le Tue, 2 Oct 2018 16:25:30 +0200 > Emmanuel Florac <eflorac@xxxxxxxxxxxxxx> écrivait: > >> Hi all, >> in fact I just discovered that Stratis exists :) >> (https://stratis-storage.github.io/relnotes/relnotes-1.0.html) >> ( details on https://lwn.net/Articles/755454/) >> >> Reading the FAQ (https://stratis-storage.github.io/FAQ.html) I see >> that it uses XFS as a filesystem layer. Furthermore it seems to come >> from RedHat. What are the relations with the future XFS capabilities >> that Dave (IIRC) demonstrated recently? >> >> Sorry for the OT message :) > > Oh, and what about the probable constant use of xfs_growfs? Stratis > seems to create all filesystems with a size of 1TB, and extends them as > needed from there. However that means that a filesystem could > potentially be expanded many times, which, as I understand it, is very > suboptimal or worse, can lead to problems (inode allocation, AGs > count and structure, etc). First, a disclaimer: I'm not a Stratis expert. None of Dave's fancy new tricks are in Stratis, because right now Dave's fancy new tricks are pretty much just in his lab. As for the growfs, that's a little bit of a concern - in general, the "start small and grow" worry is that we'll have a bazillion tiny AGs in the result. But if Stratis starts at 1TB it's not terrible; I'd need to look and see how many AGs get created (probably 4?) and if so, 250G AGs are not /too/ granular. If it's creating a lot more smaller AGs, that could become an issue if it gets grown to a very large size. IOWs the growfs concern is mostly about the resulting AG size & AG count. -Eric
Attachment:
signature.asc
Description: OpenPGP digital signature
