Re: setting up raid10 with more than 4 drives

Поиск
Список
Период
Сортировка
От Michael Stone
Тема Re: setting up raid10 with more than 4 drives
Дата
Msg-id 20070530142556.GB1785@mathom.us
обсуждение исходный текст
Ответ на Re: setting up raid10 with more than 4 drives  ("Luke Lonergan" <llonergan@greenplum.com>)
Ответы Re: setting up raid10 with more than 4 drives  ("Luke Lonergan" <LLonergan@greenplum.com>)
Re: setting up raid10 with more than 4 drives  (Gregory Stark <stark@enterprisedb.com>)
Список pgsql-performance
On Wed, May 30, 2007 at 07:06:54AM -0700, Luke Lonergan wrote:
>On 5/30/07 12:29 AM, "Peter Childs" <peterachilds@gmail.com> wrote:
>> Good point, also if you had Raid 1 with 3 drives with some bit errors at least
>> you can take a vote on whats right. Where as if you only have 2 and they
>> disagree how do you know which is right other than pick one and hope... But
>> whatever it will be slower to keep in sync on a heavy write system.
>
>Much better to get a RAID system that checksums blocks so that "good" is
>known.  Solaris ZFS does that, as do high end systems from EMC and HDS.

I don't see how that's better at all; in fact, it reduces to exactly the
same problem: given two pieces of data which disagree, which is right?
The ZFS hashes do a better job of error detection, but that's still not
the same thing as a voting system (3 copies, 2 of 3 is correct answer)
to resolve inconsistencies.

Mike Stone

В списке pgsql-performance по дате отправления:

Предыдущее
От: Andrew Sullivan
Дата:
Сообщение: Re: Vacuum takes forever
Следующее
От: "Luke Lonergan"
Дата:
Сообщение: Re: setting up raid10 with more than 4 drives