Messages in this thread | | | Subject | Re: [ANNOUNCE] DualFS: File System with Meta-data and Data Separation | From | Andi Kleen <> | Date | 15 Feb 2007 21:38:18 +0100 |
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Juan Piernas Canovas <piernas@ditec.um.es> writes:
[playing devil's advocate here]
> If the data and meta-data devices of DualFS can be on different disks, > DualFS is able to READ and WRITE data and meta-data blocks in > PARALLEL.
XFS can do this too using its real time volumes (which don't contain any metadata). It can also have a separate log.
Also many storage subsystems have some internal parallelism in writing (e.g. a RAID can write on different disks in parallel for a single partition) so i'm not sure your distinction is that useful.
If you stripe two disks with a standard fs versus use one of them as metadata volume and the other as data volume with dualfs i would expect the striped variant usually be faster because it will give parallelism not only to data versus metadata, but also to all data versus other data.
Also I would expect your design to be slow for metadata read intensive workloads. E.g. have you tried to boot a root partition with dual fs? That's a very important IO benchmark for desktop Linux systems.
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