From: Ingo Franzki <ifranzki@linux.ibm.com>
To: Ilia Zykov <mail@izyk.ru>,
LVM general discussion and development <linux-lvm@redhat.com>
Subject: Re: [linux-lvm] Filesystem corruption with LVM's pvmove onto a PV with a larger physical block size
Date: Thu, 28 Feb 2019 11:10:27 +0100 [thread overview]
Message-ID: <3f94a1df-d333-70fe-56ab-3661b384e028@linux.ibm.com> (raw)
In-Reply-To: <b54c26c3-ce43-674e-d620-28fc2f369956@izyk.ru>
On 28.02.2019 10:48, Ilia Zykov wrote:
>>
>> Well, there are the following 2 commands:
>>
>> Get physical block size:
>> blockdev --getpbsz <device>
>> Get logical block size:
>> blockdev --getbsz <device>
>>
>> Filesystems seem to care about the physical block size only, not the logical block size.
>>
>> So as soon as you have PVs with different physical block sizes (as reported by blockdev --getpbsz) I would be very careful...
>
> Hello everybody.
> Maybe, I don’t understand what do you mean. What the logical block size
> mean? But on my machines(CentOS7), this utility get me the strange
> results (output reduced):
>
> smartctl -i /dev/sda; blockdev --getbsz --getpbsz /dev/sda
> Device Model: INTEL SSDSC2KB480G8
> User Capacity: 480,103,981,056 bytes [480 GB]
> Sector Sizes: 512 bytes logical, 4096 bytes physical
> Rotation Rate: Solid State Device
> 4096
> 4096
>
> smartctl -i /dev/sdb; blockdev --getbsz --getpbsz /dev/sdb
> Device Model: HGST HUS722T2TALA604
> User Capacity: 2,000,398,934,016 bytes [2.00 TB]
> Sector Size: 512 bytes logical/physical
> Rotation Rate: 7200 rpm
> Form Factor: 3.5 inches
> 4096
> 512
>
> As you see “–getbsz” forever 4096.
I also see logical block size to be 4096 for all devices on my system.
> But I think it must be forever 512.
> What does it mean?
I have seen the following description about logical and physical block sizes somewhere in the internet:
"Logical block sizes are the units used by the 'kernel' for read/write operations.
Physical block sizes are the units which 'disk controllers' use for read/write operations."
For the problem mentioned in this thread, the physical block size is what you are looking for.
>
> Thank you.
> Ilia.
>
--
Ingo Franzki
eMail: ifranzki@linux.ibm.com
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next prev parent reply other threads:[~2019-02-28 10:10 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-25 15:33 [linux-lvm] Filesystem corruption with LVM's pvmove onto a PV with a larger physical block size Ingo Franzki
2019-02-27 0:00 ` Cesare Leonardi
2019-02-27 8:49 ` Ingo Franzki
2019-02-27 14:59 ` Stuart D. Gathman
2019-02-27 17:05 ` Ingo Franzki
2019-03-02 1:37 ` L A Walsh
2019-02-28 1:31 ` Cesare Leonardi
2019-02-28 1:52 ` Stuart D. Gathman
2019-02-28 8:41 ` Ingo Franzki
2019-02-28 9:48 ` Ilia Zykov
2019-02-28 10:10 ` Ingo Franzki [this message]
2019-02-28 10:41 ` Ilia Zykov
2019-02-28 10:50 ` Ilia Zykov
2019-02-28 13:13 ` Ilia Zykov
2019-03-01 1:24 ` Cesare Leonardi
2019-03-01 2:56 ` [linux-lvm] Filesystem corruption with LVM's pvmove onto a PVwith " Bernd Eckenfels
2019-03-01 8:00 ` Ingo Franzki
2019-03-01 3:41 ` [linux-lvm] Filesystem corruption with LVM's pvmove onto a PV with " Stuart D. Gathman
2019-03-01 7:59 ` Ingo Franzki
2019-03-01 8:05 ` Ingo Franzki
2019-03-02 1:36 ` Cesare Leonardi
2019-03-02 20:25 ` Nir Soffer
2019-03-04 22:45 ` Cesare Leonardi
2019-03-04 23:22 ` Nir Soffer
2019-03-05 7:54 ` Ingo Franzki
2019-03-04 9:12 ` Ingo Franzki
2019-03-04 22:10 ` Cesare Leonardi
2019-03-05 0:12 ` Stuart D. Gathman
2019-03-05 7:53 ` Ingo Franzki
2019-03-05 9:29 ` Ilia Zykov
2019-03-05 11:42 ` Ingo Franzki
2019-03-05 16:29 ` Nir Soffer
2019-03-05 16:36 ` David Teigland
2019-03-05 16:56 ` Stuart D. Gathman
2019-02-28 14:36 ` Ilia Zykov
2019-02-28 16:30 ` Ingo Franzki
2019-02-28 18:11 ` Ilia Zykov
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