On 01/08/12 18:21, Bob Friesenhahn wrote:
Something else to be aware of is that even if you don't have a dedicated
ZIL device, zfs will create a ZIL using devices in the main pool so
Terminology nit: The log device is a SLOG. Every ZFS dataset has a
ZIL. Where the ZIL writes (slog or main
2012-01-08 5:45, Richard Elling wrote:
I think you will see a tradeoff on the read side of the mixed read/write
workload.
Sync writes have higher priority than reads so the order of I/O sent to the disk
will appear to be very random and not significantly coalesced. This is the
pathological
From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss-
boun...@opensolaris.org] On Behalf Of Jim Klimov
1) Sync writes will land on disk randomly into nearest
(to disk heads) available blocks, in order to have them
committed ASAP;
This is true - but you need to make the distinction
From: Richard Elling [mailto:richard.ell...@gmail.com]
Also, the concept of faster tracks of the HDD is also incorrect. Yes,
there was a time when HDD speeds were limited by rotational speed and
magnetic density, so the outer tracks of the disk could serve up more
data
because more
2012-01-08 18:56, Edward Ned Harvey wrote:
From: Richard Elling [mailto:richard.ell...@gmail.com]
Disagree. My data, and the vendor specs, continue to show different
sequential
media bandwidth speed for inner vs outer cylinders.
Any reference?
Well, Richard's data matches mine with tests of
On Sat, 7 Jan 2012, Edward Ned Harvey wrote:
If you don't split out your ZIL separate from the storage pool, zfs already
chooses disk blocks that it believes to be optimized for minimal access
time. In fact, I believe, zfs will dedicate a few sectors at the low end, a
few at the high end, and
If the performance of the outer tracks is better than the performance of the
inner tracks due to limitations of magnetic density or rotation speed (not
being limited by the head speed or bus speed), then the sequential
performance of the drive should increase as a square function, going toward
Hello all,
For smaller systems such as laptops or low-end servers,
which can house 1-2 disks, would it make sense to dedicate
a 2-4Gb slice to the ZIL for the data pool, separate from
rpool? Example layout (single-disk or mirrored):
s0 - 16Gb - rpool
s1 - 4Gb - data-zil
s3 - *Gb - data pool
From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss-
boun...@opensolaris.org] On Behalf Of Jim Klimov
For smaller systems such as laptops or low-end servers,
which can house 1-2 disks, would it make sense to dedicate
a 2-4Gb slice to the ZIL for the data pool, separate from
On Jan 7, 2012, at 7:12 AM, Edward Ned Harvey wrote:
From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss-
boun...@opensolaris.org] On Behalf Of Jim Klimov
For smaller systems such as laptops or low-end servers,
which can house 1-2 disks, would it make sense to dedicate
a 2-4Gb
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