From: Roberto Spadim <roberto@spadim.com.br>
To: GarBoge <garboge@shaw.ca>
Cc: linux-raid@vger.kernel.org, neilb@suse.de
Subject: Re: filesystem on mdadm raid from unpartioned block devices
Date: Wed, 12 Jan 2011 20:39:02 -0200 [thread overview]
Message-ID: <AANLkTikfX4-wQA7zCeuXOEmrz04Za+2Bp+3vqku9-sWA@mail.gmail.com> (raw)
In-Reply-To: <AANLkTik0V_c_+xjMgn6-qYbUd7o2C5w6csJ8UgLU5B7S@mail.gmail.com>
options for raid in mkfs.ext4:
stride=stride-size
Configure the filesystem for a RAID array with
stride-size filesystem blocks. This is the number of
blocks read or written to disk before moving to the
next disk, which is sometimes referred to as the
chunk size. This mostly affects placement of
filesystem metadata like bitmaps at mke2fs time to
avoid placing them on a single disk, which can hurt
performance. It may also be used by the block allo-
cator.
stripe-width=stripe-width
Configure the filesystem for a RAID array with
stripe-width filesystem blocks per stripe. This is
typically stride-size * N, where N is the number of
data-bearing disks in the RAID (e.g. for RAID 5
there is one parity disk, so N will be the number of
disks in the array minus 1). This allows the block
allocator to prevent read-modify-write of the parity
in a RAID stripe if possible when the data is writ-
ten.
i don´t know if it work
2011/1/12 Roberto Spadim <roberto@spadim.com.br>:
> i think that mkfs.ext4 is 4096 default block size
> -b 4096 is the option for device block size
>
>
> 2011/1/12 GarBoge <garboge@shaw.ca>:
>> A quick question that I haven't been able to find and answer for.
>>
>> I have been using whole block devices (whole unpartitioned hard drives)
>> in various raid 1 and 5 setups using mdadm 3.1.4 with pretty mundane
>> options (default options such as striping and but using metadata 1.2).
>> Typically I use mkfs.ext4 with no options (default) to install the
>> filesystem.
>>
>> Is there an issue with alignment on the newer 4096-byte drives. If so
>> what would be the proper approach?
>>
>> I thank you for your time.
>>
>> Ashley
>>
>> --
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>
>
>
> --
> Roberto Spadim
> Spadim Technology / SPAEmpresarial
>
--
Roberto Spadim
Spadim Technology / SPAEmpresarial
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next prev parent reply other threads:[~2011-01-12 22:39 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-12 22:31 filesystem on mdadm raid from unpartioned block devices GarBoge
2011-01-12 22:37 ` Roberto Spadim
2011-01-12 22:39 ` Roberto Spadim [this message]
2011-01-13 2:00 ` NeilBrown
2011-01-14 15:44 ` GarBoge
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