Hi all,

I currently have a Linode 2048 running Debian 5 32-bit as a dedicated MySQL 5.1 server. The volume of data is relatively large -- about 16GB worth of data. Two of the tables contain the bulk of the data, each with about 50M records. These tables will increase by about 50M records every 6 months or so. Lots of indexes on these tables; the size of the indexes take up more space than the actual data does.

Anyway, I'm considering upgrading to a Linode 4096 to throw more memory at this thing. Not that I'm feeling terribly strained right now, but more memory for a database is never a bad thing, right? Of course, in order for MySQL to utilize more than 2GB of memory, I'd need to move to a 64-bit distro.

I'll no doubt lose a chunk of usable memory due to the overhead inherent with 64-bit, but I wonder if it would still be worth the switch. If it was something like 8GB of memory, the choice would be a no-brainer. But 4GB seems like it's just on the edge of being worthwhile. Anyone have any input or recommendations?

Thanks in advance.

Lots of variables in fine tuning a database.

I believe (but don't know as fact) that Linode pro-rates to the day.

If true, I'd setup two new 4G Linodes - one 32bit and one 64bit - setup your database - then run your own benchmarks using your own system setup and own data.

Then you'll know for sure.

Keep the one that is fastest.

Kill the slow one.

Only pay for a few days of testing.

Vonskippy's right linode do pro-rate by the day I've knocked up various test servers. Try it out is the best solution.

I thought the limit for 32-bit was ~4GB, not 2GB.

Generally speaking, you're correct. I wasn't very clear in my original post, but I was referring to the amount of memory you can allocate to the innodb_buffer_pool_size in MySQL. My information on the subject may be a bit dated, but in my experience, I could never allocate even 2GB of memory on 32-bit linux. The discussions at the following links explain why:

http://lists.mysql.com/mysql/185491
http://bugs.mysql.com/bug.php?id=4516

Thanks vonskippy and obs for your replies. I figured it would be one of those things I'd just have to try for myself, and fortunately Linode does make that easy to do. I'll spin things up and take a look.