Flash drives have a limited number of writes that can be done before the
drive starts to fail:
http://www.kingston.com/tools/bits/bit17.asp
http://www.diskonkey.com/documents/Performance_reliability.pdf
(Look under "Flash Reliability")
If I can write the database to a RAM disk and just archive to the flash
drive periodically, I can greatly reduce the number of writes to the
flash drives and extending its life. These drives are going into
transmitter stations in remote locations that are only accessible in the
summer. If we have a failure in the winter the system could be unusable
for 6 months.
The system is protected by a monitored UPS. If the power fails, part of
the shutdown procedure would be to save the database to flash.
There is no user per se for this system but there are multiple processes
accessing the database. There are actually two databases but one gets
backed up much more frequently than the other. The whole operating
system and application is stored on the flash drive.
HEAP tables might be the solution. How would I archive these to disk on
shutdown?
...Stephen
-----Original Message-----
From: mos [mailto:[EMAIL PROTECTED]
Sent: Jul 30, 2004 7:38 AM
To: [EMAIL PROTECTED]
Subject: Re: Installing MySQL Databases on RAM Drive
At 04:45 PM 7/28/2004, you wrote:
>Our customers are running MySQL 4.0.17 on QNX 6.2.1.
>
>We are currently using a flash drive to store our database but we want
>to store it in a RAM disk to prolong the life of the drive
Flash drives are solid state (no moving parts) so you can't break them.
I've never heard of anyone wearing them out. Compact Flash unless they
are
too slow or consume too much power, I'd recommend sticking with a flash
drive. With a RAM drive you need to handle times when the power fails.
Someone else mentioned HEAP tables which solves the speed problem and
you
could write everything to flash memory every 5 minutes or so as a back
up.
I assume this is for a single user right? You're not running a database
server off of Compact Flash, right? If so you may want to try the
embedded
MySQL version which will speed things up a bit.
http://dev.mysql.com/doc/mysql/en/libmysqld_overview.html
Mike
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