does XFS support block sizes other than 512 bytes?

does XFS support block sizes other than 512 bytes?

[Linda A. Walsh]

This one's a bit more specific than the last.  If memory serves me,
XFS supported differing block sizes (which you could do on a hardware format
of a SCSI drive) back on IRIX.  But when first ported to Linux it didn't
work.  Was that ever fixed?  I seem to remember that going to 1-2K block sizes
gave and extra 10%, and it almost seems logical that going to a 4kK block size
would be ideal for xfs (presuming your disk doesn't start getting errors,
then it might get harder to remap sectors and you'd hit hard disk failure
(w/o remappable sectors) sooner.

But at least 1K might be a reasonable tradeoff?  Been quite a while since
I tried it and don't even know if the SAS drives allow it (if they do, I wonder
if the newer SATA drives do?)

thanks more... :-)
-linda

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Re: does XFS support block sizes other than 512 bytes?

[Michael Monnerie]

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On Samstag 18 Juli 2009 Linda A. Walsh wrote:
> This one's a bit more specific than the last.  If memory serves me,
> XFS supported differing block sizes (which you could do on a hardware
> format of a SCSI drive) back on IRIX.  But when first ported to Linux
> it didn't work.  Was that ever fixed?  I seem to remember that going
> to 1-2K block sizes gave and extra 10%, and it almost seems logical
> that going to a 4kK block size would be ideal for xfs (presuming your
> disk doesn't start getting errors, then it might get harder to remap
> sectors and you'd hit hard disk failure (w/o remappable sectors)
> sooner.
>
> But at least 1K might be a reasonable tradeoff?  Been quite a while
> since I tried it and don't even know if the SAS drives allow it (if
> they do, I wonder if the newer SATA drives do?)

XFS can only use sector sizes that the hard disks provide. There will be 
4K drives from vendors "soon", and XFS is prepared to use that. 

mfg zmi
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Re: does XFS support block sizes other than 512 bytes?

[Russell Cattelan]

Linda A. Walsh wrote:
> This one's a bit more specific than the last.  If memory serves me,
> XFS supported differing block sizes (which you could do on a hardware
> format
> of a SCSI drive) back on IRIX.  But when first ported to Linux it didn't
> work.  Was that ever fixed?  I seem to remember that going to 1-2K
> block sizes
> gave and extra 10%, and it almost seems logical that going to a 4kK
> block size
> would be ideal for xfs (presuming your disk doesn't start getting errors,
> then it might get harder to remap sectors and you'd hit hard disk failure
> (w/o remappable sectors) sooner.
>
> But at least 1K might be a reasonable tradeoff?  Been quite a while since
> I tried it and don't even know if the SAS drives allow it (if they do,
> I wonder
> if the newer SATA drives do?)
Yes
XFS can support any power of 2 sector size up to the page size of your
system.
And it is recommend that on things like raid5 devices that the sector
size be
set to the same size as the filesystem block size.

>
> thanks more... :-)
> -linda
>
> _______________________________________________
> xfs mailing list
> xfs@oss.sgi.com
> http://oss.sgi.com/mailman/listinfo/xfs
>

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Re: does XFS support block sizes other than 512 bytes?

[Linda A. Walsh]

Russell Cattelan wrote:
>> But at least 1K might be a reasonable tradeoff?  Been quite a while since
>> I tried it and don't even know if the SAS drives allow it (if they do,
>> I wonder if the newer SATA drives do?)
> Yes
> XFS can support any power of 2 sector size up to the page size of your
> system.
> And it is recommend that on things like raid5 devices that the sector
> size be
> set to the same size as the filesystem block size.
> 
>> thanks more... :-)
>> -linda
---
	Just tried a 146GB-15K Seagate Cheetah SAS.  It didn't like anything other than 512bytes.  Any larger size ended up with a 528 byte sector size which really miffed the linux kernel so bad, it wouldn't expose it as a device
in /dev.  If you don't know mknod and the correct dev num, it would
make for a very interesting time formatting it back down.  ;-)

Do you know what brands might allow resizing?  You say SATA might
allow...just a WAG...but maybe a Seagate SATA might not? ;^)

Also, I wonder what might happen with a HW RAID card -- if it would
deal with 4K block sizes.  It deals with up to 1MB stripe sizes...so
you'd think it'd handle 4K block sizes...???  

Thanks for the fun times so far...;^)



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