Re: RAID newbie, 1 vs 5, chunk sizes

[Phil Turmel <philip@turmel.org>]

On 06/14/2014 05:01 PM, Nuno Magalhães wrote:
> Hi,
> 
> Sorry if this is the wrong list. Most of the stuff out there seems
> outdated, and i have some specific doubts.
> 
> I'm trying to decide how to best create a RAID array and what
> configuration to use. This is a desktop system, nothing
> mission-critical, but i'd like it to be reasonably tailored to the
> hardware and intended usage, and have questions about default values.
> 
> Hardware:
>     1x Toshiba DT01ACA100 - 32MB bus, 931.0 GiB (1 TB; 1000204886016 bytes)
>     2x Seagate ST1000DM0003 - 64MB bus, 931.0 GiB (1 TB; 1000204886016 bytes)
> and
>     1x Maxtor 6G160E0 - 8MB bus, 149.1 GiB (160 GB; 160041885696 bytes)

Before going any further, check the TLER/ERC support for these drives.
(The Seagate xxxxxDM003 is ringing warning bells for me.)  The output of
"smartctl -l scterc /dev/sdX" for each one will do.  If you get anything
other than "7.0 seconds" or similar, you'll need special boot-time
scripting.  If you get "not supported", I wouldn't even consider putting
the drive into any raid array.

Search this list's archives for details on "timeout mismatch", "scterc",
and the consequences of ignoring this.

If you do have good error recovery timeouts, continue with Stan's advice.

Phil
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