Re: Change sector size on existing partition

[Dewangga Bachrul Alam <dewanggaba@xtremenitro.org>]

Hi,

On 01/23/2015 09:06 PM, Brian Foster wrote:
> On Fri, Jan 23, 2015 at 08:46:59PM +0700, Dewangga Bachrul Alam wrote:
>> Hi,
>>
>> The device reported like this :
>>
>> $ blockdev --getss --getpbsz --getiomin --getioopt /dev/dm-3
>> 512
>> 4096
>> 4096
>> 0
>>
> 
> What is dm-3? Is that a logical volume based on a volume group on top of
> your physical array? It might be good to get the equivalent data for the
> array device (md?) and at least one of the physical devices (sd?).
> 

dm-3 is logical partition, not my physical array. Here is my partition
table :

--
NAME                                   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda                                      8:0    0  1.8T  0 disk
├─sda1                                   8:1    0  500M  0 part /boot
└─sda2                                   8:2    0  1.8T  0 part
  ├─vg_catalystdb01-lv_root (dm-0)     253:0    0   50G  0 lvm  /
  ├─vg_catalystdb01-lv_swap (dm-1)     253:1    0 31.5G  0 lvm  [SWAP]
  ├─vg_catalystdb01-lv_home (dm-2)     253:2    0 48.8G  0 lvm  /home
  ├─vg_catalystdb01-lv_database (dm-3) 253:3    0 97.7G  0 lvm
/var/lib/mysql
  ├─vg_catalystdb01-lv_tmp (dm-4)      253:4    0  3.9G  0 lvm  /tmp
  ├─vg_catalystdb01-lv_var (dm-5)      253:5    0 19.5G  0 lvm  /var
  ├─vg_catalystdb01-lv_audit (dm-6)    253:6    0  3.9G  0 lvm
/var/log/audit
  └─vg_catalystdb01-lv_log (dm-7)      253:7    0  7.8G  0 lvm  /var/log
--

XFS file system is only mounted on vg_catalystdb01-lv_database (dm-3).

>> Then, the sector size should be 512. Don't know why it can be 4096. :( I
>> will try to backup them and reformat. Any suggestion for formating on
>> raid-10 array? The device is 4 x 1TB drives.
>>
> 
> According to the above you have 4k physical sectors and 512b logical
> sectors. IIUC, this means mkfs will use the physical size by default,
> but you can specify and the device can handle down to 512 sectors.
> 
> From skimming through the link posted earlier, it sounds like you have
> an application that has a hardcoded dependency on 512b direct I/O
> requirements (e.g., buffer alignment) rather than being configurable..?
> Can you disable direct I/O and verify whether that works? Regardless, it
> might be wise to test out this 512b sector configuration (perhaps with a
> single or spare drive?) and verify this fixes the problem you're trying
> to solve before reconfiguring everything.
> 

If I disable directio, the application works well.

Then, I've reformat the existing partition, and enable directio
parameter. It's works. It's the new result.

$ xfs_info /dev/dm-3
meta-data=/dev/mapper/vg_catalystdb01-lv_database isize=256
agcount=16, agsize=1600000 blks
         =                       sectsz=512   attr=2, projid32bit=0
data     =                       bsize=4096   blocks=25600000, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0
log      =internal               bsize=4096   blocks=12500, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0


Thanks bro.

> Brian
> 
>> On 01/23/2015 08:39 PM, Brian Foster wrote:
>>> On Fri, Jan 23, 2015 at 08:04:44PM +0700, Dewangga Bachrul Alam wrote:
>>>> Hi,
>>>>
>>>> I'm new to XFS, I have RAID-10 array with 4 disk, when I check with
>>>> xfs_info, the information print like this.
>>>>
>>>> $ xfs_info /var/lib/mysql
>>>> meta-data=/dev/mapper/vg_catalystdb01-lv_database isize=256
>>>> agcount=16, agsize=1600000 blks
>>>>          =                       sectsz=4096  attr=2, projid32bit=0
>>>> data     =                       bsize=4096   blocks=25600000, imaxpct=25
>>>>          =                       sunit=0      swidth=0 blks
>>>> naming   =version 2              bsize=4096   ascii-ci=0
>>>> log      =internal               bsize=4096   blocks=12500, version=2
>>>>          =                       sectsz=4096  sunit=1 blks, lazy-count=1
>>>> realtime =none                   extsz=4096   blocks=0, rtextents=0
>>>>
>>>> Is it possible to change `sectsz` value to 512 without re-format it? Or
>>>> any suggestion? I have issue with current sector size, my TokuDB
>>>> engines[1] can't start because of this.
>>>>
>>>
>>> The only way to set things like sector size, block size, etc. is to
>>> reformat. I believe the default sector size is dependent on the physical
>>> device. You might want to report the following from your array device
>>> and perhaps from some or all of the member devices:
>>>
>>> blockdev --getss --getpbsz --getiomin --getioopt <device>
>>>
>>> Brian
>>>
>>>> [1] https://groups.google.com/forum/#!topic/tokudb-user/kvQFJLCmKwo
>>>>
>>>> _______________________________________________
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