approach is better :)
Much, much better.
As I said, this was not to go after you personally, but to point
out that we need to be more rigorous with benchmarks in general.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer
t, you numbers are meaningless, because we have no
idea what the signal/noise ratio is.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explain
:
run test A
run test B
run test C
...
Throw first result away for all tests
Run remaining results through ministat(1)
This was a public service announcement.
Poul-Henning
PS: Recommended reading: http://www.larrygon
ipe size of 63 sectors, a (too) large
fraction of the requests will have one sector in one raid-stripe
and the rest in another, which they often fail to fill by exactly
one sector.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
[EMAIL PROTECTED] | TCP/IP since RFC 956
FreeBSD c
too,
but it seems only fair to put the overhead in front of those three
since they are already slow operations.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
[EMAIL PROTECTED] | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to mali
o doubt that this
is the way we are headed, hopefully sometime in the 7-CURRENT period.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
[EMAIL PROTECTED] | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be expla
; madness in order to support 512 bytes sectors on the RAID3 volume.
>
>I would really love the 512 + 8 byte checksum stuff that mainframes
>and netapps do. Does GEOM simplify implementing something like this ?
Yes, GEOM works with arbitrary sectorsizes, but far from all current
GEOM classes
.
Just checking: what exactly did you disable ?
>N.B. Current had at least on out of order lock issue while I was using
>it but not while the tests where going on.
Yes, current is current :-)
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
[EMAIL PROT
you remember to disable all the debugging in FreeBSD 6-Current ?
(see top of src/UPDATING)
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
[EMAIL PROTECTED] | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice wha
8 byte sector sizes and similar
madness in order to support 512 bytes sectors on the RAID3 volume.
Some of them use 512 byte sector disks and internal sectorsizes of
N*512 bytes and use their battery-backed cache to pretend to have
512 bytes logical sectorsize.
--
Poul-Henning Kamp | UNIX sinc
In message <[EMAIL PROTECTED]>, Allen writes:
I just want to add: This is why I really would love for us to have
a real RAID3 implemetation.
RAID3 is not commercially viable because windows cannot use non-512
byte sectors.
We can.
RAID3 would scream for us.
--
Poul-Hennin
happens in the RAID5 unit.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
[EMAIL PROTECTED] | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
it right. Fixing them to do so may be more
trouble than writing a better too bottom up.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
[EMAIL PROTECTED] | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be
In message <[EMAIL PROTECTED]>, Petri Helenius writes:
>>
>My tests were using RAID10 and just striping. (RAID0 might be the right
>name for it)
Same thing applies, and it depends on how the reqeust alignment/size and
stripe alignment/size interacts.
--
Poul-Henning Kamp
In message <[EMAIL PROTECTED]>, Eric Anderson writes:
>Poul-Henning Kamp wrote:
>> In message <[EMAIL PROTECTED]>, Eric Anderson writes:
>>
>>
>>>Don't mean to be terse here, but I'm talking about the same test done an
>>>two diffe
f you are using RAID5 and your requests are not aligned and
sized after the RAID5 you should *expect* read performance to be poor.
If you your request ends up accessing two different blocks even just
once per stripe, this totally kills performance.
--
Poul-Henning Kamp | UNIX since Zilog Z
>This is totally bogus to me - [...]
If the disk has bad sectors or other hardware issues, this is not
an atypical result.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
[EMAIL PROTECTED] | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute t
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