Dear Gregory, thanks for your fast reply. I understand the reasons for hiding the attributes and agree with them. For example, migrating data pool settings between different ceph file systems without value mapping as in our case will break everything. Now, the situation is this, consider a multi-TB or even multi-PB file system with some files and folders at any place of this structure with a ceph-xattr set. How do you find all the ones that have these xattrs set *efficiently*? A find with an exec for every single file will never finish. In other words, its not about finding the value once you know where it is set. Its finding the places where it is set. For example, if I give you a mounted cephfs, how do you find all directories with a quota set? How fast is it? Can you query the ceph MDS directly instead? Does some rados object hold this information? Its similar to the problem of finding all locations of snapshots in a cephfs. This used to be a huge pain. Now there is MDS functionality and clever rados querying for this. Best regards, ================= Frank Schilder AIT Risø Campus Bygning 109, rum S14 ________________________________________ From: Gregory Farnum <gfarnum@xxxxxxxxxx> Sent: 26 March 2020 18:36 To: Frank Schilder Cc: ceph-users Subject: Re: How to migrate ceph-xattribs? On Thu, Mar 26, 2020 at 9:24 AM Frank Schilder <frans@xxxxxx> wrote: > > De all, > > we are in the process of migrating a ceph file system from a 2-pool layout (rep meta+ec data) to the recently recommended 3-pool layout (rep meta, per primary data, ec data). As part of this, we need to migrate any ceph xattribs set on files and directories. As these are no longer discoverable, how would one go about this? > > Special cases: > > How to migrate quota settings? > How to migrate dir- and file-layouts? > > Ideally, at least quota attributes should be transferable on the fly with tools like rsync. These are all policy decisions that seem pretty cluster-specific to me. We hid them in the first place because exposing ceph xattrs to rsync was breaking it horribly. > If automatic migration is not possible, is there at least an efficient way to *find* everything with special ceph attributes? IIRC, you can still see all these attributes by querying for the "ceph" xattr. Does that not work for you? > > Thanks and best regards, > > ================= > Frank Schilder > AIT Risø Campus > Bygning 109, rum S14 > _______________________________________________ > ceph-users mailing list -- ceph-users@xxxxxxx > To unsubscribe send an email to ceph-users-leave@xxxxxxx > _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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