Messages in this thread | | | Date | Wed, 05 Jul 2006 15:19:04 +0300 | From | Avi Kivity <> | Subject | Re: ext4 features (checksums) |
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Bill Davidsen wrote: > > > I believe that implementing RAID in the filesystem has many benefits > too: > > - multiple RAID levels: store metadata in triple-mirror RAID 1, random > > write intensive data in RAID 1, bulk data in RAID 5/6 > > - improved write throughput - since stripes can be variable size, any > > large enough write fills a whole stripe > > > I rather like the idea of allowing metadata to be on another device in > general, or at least the inodes. That way a very small chunk size can be > used for the inodes, to spread head motion, while a larger chunk size is > appropriate for data in some cases. >
If your workload is metadata intensive, your data disks are idle; if you're reading data, the inode device is gathering dust. You can run out of inodes before you run out of space and vice-versa. Very suboptimal.
A symmetric configuration allows full use of all resources for any workload, at the cost of increased complexity - every extent has its own RAID level and RAID component devices.
> Larger max block sizes would be useful as well. Feel free to discuss the > actual value of "larger." >
Filesystems should use extents, not blocks, avoiding the block size tradeoff entirely.
-- error compiling committee.c: too many arguments to function
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