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Re: Intel SSDs that may not suck

From: Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com>
To: Jesper Krogh <jesper(at)krogh(dot)cc>
Cc: Merlin Moncure <mmoncure(at)gmail(dot)com>, Andy <angelflow(at)yahoo(dot)com>, "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org>, Greg Smith <greg(at)2ndquadrant(dot)com>
Subject: Re: Intel SSDs that may not suck
Date: 2011-03-29 05:02:01
Message-ID: BANLkTikX1VoQhy3NjpmNJkyiVZ=FAM8E_g@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-performance
On Mon, Mar 28, 2011 at 10:55 PM, Jesper Krogh <jesper(at)krogh(dot)cc> wrote:
> On 2011-03-29 06:13, Merlin Moncure wrote:
>>
>> My own experience with MLC drives is that write cycle expectations are
>> more or less as advertised. They do go down (hard), and have to be
>> monitored. If you are writing a lot of data this can get pretty
>> expensive although the cost dynamics are getting better and better for
>> flash. I have no idea what would be precisely prudent, but maybe some
>> good monitoring tools and phased obsolescence at around 80% duty cycle
>> might not be a bad starting point.  With hard drives, you can kinda
>> wait for em to pop and swap em in -- this is NOT a good idea for flash
>> raid volumes.
>
> What do you mean by "hard", I have some in our setup, but
> havent seen anyting "hard" just yet. Based on report on the net
> they seem to slow down writes to "next to nothing" when they
> get used but that seems to be more gracefully than old
> rotating drives..  can you elaborate a bit more?

My understanding is that without running trim commands and such, they
become fragmented and slower.  But, when they start running out of
write cycles they just die.  I.e. they go down hard.

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Subject: Re: Intel SSDs that may not suck
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