SSD Cache (SRT) & TRIM?

[idata]

Hello there!

I am currently using a Mushkin Chronos 60gb SSD as a cache drive for my 1TB Samsung Hard Drive.

I understand that recently Intel allowed the TRIM command to work when the SATA controllers are in RAID mode. Does this extend to SSD caching?

I am using a Z68 motherboard, however I modified the bios to give it an 11.6 OROM that you would find on a Z77, and in the BIOS and inside Intel RST, it states I am running RAID Rom of 11.6.

I am also using Intel RST version 11.7 (The latest).

So my big overall question is: Does TRIM work inside an SSD cache drive? Is there a way of testing?

[KenF_Intel]

Hi James,

I'm waiting for a definitive answer from our Intel® Rapid Storage Technology team. I'll let you know when I hear something.

[idata]

Thanks Ken! I await a repsonse

[DZand]

James schrieb:

So my big overall question is: Does TRIM work inside an SSD cache drive?

AFAIK TRIM is not supported by SSDs, which are just used for caching purposes with Intel's Smart Response Technology.

Additionally you may read this thread at AnandTech: http://forums.anandtech.com/showthread.php?t=2243052 http://forums.anandtech.com/showthread.php?t=2243052 http://forums.anandtech.com/showthread.php?t=2243052

[idata]

I read that thread before, but the people in it don't seem too sure on their answers, thats why I had hoped someone from Intel could shed light.

[KenF_Intel]

Hi James,

I have confirmation that TRIM is not necessary for drives used as a cache device.

[idata]

Which apparently means TRIM is not passed to a caching SSD.

The "not necessary" statement is curious, I'd love to know why that is. Given that a caching SSD is potentially and by design moving commonly accessed files (that change over time) on and off of the SSD, TRIM would seem useful. OTOH, the actual implementation of the cached file system may take care of this.

Yet another example of the mysterious internal workings of SSDs.

[KenF_Intel]

Hi Parsec,

Engineering didn't provide any details but they did say it's not necessary due to the implementation.

[MBlac1]

I have an Intel 530 240gb SSD and am using only 40gb for caching my 2tb WD Black RAID 1

So i say fine no need to trim the cache what about the other 200gb on the SSD

[Kevin_M_Intel]

SSD's do not need and cannot be accelerated due to the high speed transfer and functionality. You can use the SSD to accelerate a mechanical HDD but the SSD is like if it was already accelerated.

Kevin M