Avi Kivity wrote:
Neil Brown wrote:
On Tuesday July 4, [email protected] wrote:
> Neil Brown wrote:
> >
> > To my mind, the only thing you should put between the filesystem and
> > the raw devices is RAID (real-raid - not raid0 or linear).
> >
> 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
Maybe....
Now imagine what would be required to rebuild a whole drive onto a
spare after a drive failure.
I'm sure it is possible, and I believe ZFS does something like that.
I find it hard to imagine getting reasonable speed if there is much
complexity. And the longer it takes, the longer your data is exposed
to multiple-failures.
A company called Isilon does this on a cluster. They claim (IIRC) a one
hour rebuild time for a failure. AFAIK they rebuild into cluster free
space, so they are not bound by the spare's bandwidth; they can utilize
all cluster resources for a rebuild.
(You don't need spare disks, just spare free space; so you don't have
idle disk heads)
Readers of the RAID list will recognize this description, it matches my
comments on RAID5E (distributed hot spare) very well. And I suppose
there could be RAID6E as well, although I haven't really thought about it.
--
Bill Davidsen <[email protected]>
Obscure bug of 2004: BASH BUFFER OVERFLOW - if bash is being run by a
normal user and is setuid root, with the "vi" line edit mode selected,
and the character set is "big5," an off-by-one errors occurs during
wildcard (glob) expansion.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
