Re: Using SAN Splits to instantly copy a DB

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On 11/15/06 14:46, Martijn van Oosterhout wrote:
>> How does it know what a crashed PostgreSQL database look like?
>>
>> Besides, active transactions need to be *rolled back*, not written
>> ahead, since half the data hasn't been sent from the computer yet.
>
> There's a section of the docs dealing with this:
>
> http://www.postgresql.org/docs/8.1/static/wal.html

Oh, wait, I missed this in your previous email: "start a new
postmaster". That resolves a *lot* of my confusion.

However, what if the WAL is not on the SAN? You'd have to shut down
pg anyway, in order to copy the WAL to a new directory, no?

Lastly: in order to do SAN splitting without risking your data,
wouldn't you have to configure the disks as RAID-15 (mirrored
RAID-5), since splitting a RAID10 would leave you with stripesets?

- --
Ron Johnson, Jr.
Jefferson LA USA

Is "common sense" really valid?
For example, it is "common sense" to white-power racists that
whites are superior to blacks, and that those with brown skins
are mud people.
However, that "common sense" is obviously wrong.
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