Re: OT - RAM disks - WAS Re: [gentoo-user] Network failed and weird error message

[Pandu Poluan <pandu@poluan.info>]

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On Oct 14, 2013 6:04 PM, "Tanstaafl" <tanstaafl@libertytrek.org> wrote:
>
> On 2013-10-13 5:49 PM, Dale <rdalek1967@gmail.com> wrote:
>>
>> Talk about putting some stuff on tmpfs.  O_O  I have always wanted to
>> copy the tree to tmpfs and run "time emerge -uvaDN world".  Just to see
>> how fast it will go.  lol
>
>
> I remember once I worked for an Apple reseller that had this accounting
program that required them to do some kind of 'reconciliation' every month
that required a massive amount of processing - it took like 36 hours or
something ridiculous (literally almost took all weekend), and he had
implemented a rule that someone had to be there the entire time to baby sit
the process - apparently it wasn't uncommon for there to be an error that
would require them to restart it - and this was on a pretty powerful system
at the time.
>
> Well, one weekend, when we were building a system for a customer with
tons of RAM (for the time) I talked them into a little experiment. The boss
didn't believe me when I told him I could get the reconciliation processing
time down to less than a day (I told him probably just a few hours, but
wasn't sure)... so we made a bet.
>
> I took a Quadra 900 (or maybe it was a 950), and added a bunch of RAM - I
think we got it up to 128MB or something ridiculous (this was in about
1992). The accounting DB was about 40MB at the time, but hey, we had the
RAM, so I just loaded it up.
>
> I created a RAM disk, copied the entire Accounting DB into it, and
started running the reconciliation. The process finished after about 45
minutes (I was even surprised at that), and while there were no errors and
it said it had completed successfully, the boss was sure that something had
gone wrong. So, he re-ran it the old way on the old server, and almost 2
days later, when the numbers matched, he just shook his head and paid me
off, muttering about the lost weekends over the last 5 years he'd been
there. He kept that machine around for running the reconciliation for at
least a few months, but then I left, so no idea how long he kept it for...
>

Niiiice.. 48x performance improvement? I know of some DBA who would gladly
pay an arm + a leg + their grandmothers for that kind of improvement :-)

Kind of tangential, but that's what Oracle is aiming with their TimesTen
product: give the server oodles of RAM, and load the database in memory.

Another similar performance-improving method would be using Fusion-IO to
load the database into direct-memory-mapped SSDs. They claimed that the
most high-end Fusion-IO devices can reach up to 9 million IOPS...

Rgds,
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