How about SamFS <https://docs.openindiana.org/handbook/community/samqfs/>?

Gea <[email protected]> ezt írta (időpont: 2023. nov. 12., V, 19:37):

> There is a difference
>
> Arc/L2Arc only caches datablocks on a read last/ read most optimazation,
> not whole files and helps only on reads.
> On a hybrid tiering pool with a fast special vdev you gain on read and
> writes and with whole user selected files or large VMs
>
> I agree that rule or filebased data tiering with a data move between
> tier1 and tier2 storage is more complex than simple caching or the
> default ZFS tiering based on data structures but let's look at worst case
>
> A data move between tier1 and tier2 is an action like
> increase recsize && rename file ex to file.tier && copy file.tier to
> file && delete file.tier
>
> This means every action must succeed for the next in the chain to happen.
>
> If something happens during copy the final delete of the file.tier
> should not happen so you have a renamed file.tier instead file. In worst
> case use snaps. If the special vdev is full, new files land on regular
> hd vdev/tier2 instead fast ssd/tier1. Its not nice that I see no method
> to detect such files. Only solution is to force a manual move of such
> files to tier1 when there is free space again on tier1 storage. A
> problem could be open files without proper locking. If this is extremely
> critical you may need to do tiering in a low busy time with shares
> disabled.
>
> This is not a use case for every user but for special use cased where
> you want to move files transparently between fast/expensive tier1 and
> slow/cheaper tier2 storage with paths remain intact. During the move
> files are not accessable/locked.
>
> Gea
>
> > On Sun, 12 Nov 2023 at 03:33, Gea <[email protected]> wrote:
> >> Have i missed something?
> > This seems complex and potentially error prone.  How is this superior
> > to using an L2ARC cache device to increase access speed to frequently
> > accessed data?
> >
> >
> > Cheers.
> >

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