4k drives and zfs

[krad]

On 2 February 2011 15:20, krad <kraduk at gmail.com> wrote:
> On 2 February 2011 12:18, Ivan Voras <ivoras at freebsd.org> wrote:
>> On 02/02/2011 05:52, krad wrote:
>>>
>>> Hi All,
>>>
>>> A quick question. Im upgrading my filer at home to have 2x 2tb samsung
>>> F4EG drives. I believe these are 4k drives. I'm intending to use the
>>> gnop trick to get zfs ashift to 12. Will this make my pool unbootable.
>>> I have read a few threads aluding to this.
>>
>> There have been bugs which make such drives unbootable but they have been
>> fixed at least in CURRENT (I haven't tried it).
>>
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>
> where they related to any type of pools in particular as im just mirroring
>

well they are in. i tested with the gnop trick and without. It didnt
seem to make much difference to the performance of the drives.
Certainly not enough for me to worry about. Thinking about it though
as I was addin it to the existing pool as a mirror and then dropping
the old drives out one by one, i was probably forced into the 512k
sectors anyway.

Just finishing up now by filling the pool with urandom, and reading it
back. Its taking a while though.

Do these values seem similar to what others get? Bare in mind I have a
dd of /dev/zero and /dev/urandom running in parallel with a bs=128k

# zpool iostat system 5
               capacity     operations    bandwidth
pool         used  avail   read  write   read  write
----------  -----  -----  -----  -----  -----  -----
system      1.12T   709G    149    212  8.48M  15.8M
system      1.12T   708G      2    336  2.44K  30.2M
system      1.12T   708G      2    541  3.12K  57.0M
system      1.12T   708G      1    349  6.05K  32.8M
system      1.12T   708G      1    581    599  62.9M
system      1.12T   707G      3    320  5.46K  30.7M

# iostat -d 5
             ad4              ad5              ad6              ad7
  KB/t tps  MB/s   KB/t tps  MB/s   KB/t tps  MB/s   KB/t tps  MB/s
 92.50  10  0.93  102.35 245 24.50  91.86  10  0.93  102.02 246 24.49
  0.00   0  0.00  106.64 268 27.95   0.00   0  0.00  115.60 413 46.64
  0.00   0  0.00  109.72 590 63.19   0.00   0  0.00  103.79 437 44.33
  0.00   0  0.00  113.48 349 38.72   0.00   0  0.00  115.70 432 48.84
  0.00   0  0.00  106.66 547 57.02   0.00   0  0.00  103.98 461 46.84
  0.00   0  0.00  117.52 406 46.62   0.00   0  0.00  117.12 407 46.59
  0.00   0  0.00  110.43 565 60.92   0.00   0  0.00  109.64 601 64.37
  0.00   0  0.00  119.11 282 32.81   0.00   0  0.00  117.87 254 29.27

# zpool status
  pool: system
 state: ONLINE
 scrub: scrub completed after 2h2m with 0 errors on Sat Feb  5 11:47:21 2011
config:

        NAME            STATE     READ WRITE CKSUM
        system          ONLINE       0     0     0
          mirror        ONLINE       0     0     0
            label/red   ONLINE       0     0     0
            label/blue  ONLINE       0     0     0