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I'm trying to figure out what the read cache part of the following message refers to:

[sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA

Is it "IDE drive's read-lookahead feature (usually ON by default)" as treated by hdparm?

If it's not, how can this be turned off?

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Hi Poige. I suspect the -'ve votes are because what's in the title of your question isn't actually in the question. I'll tidy it up a bit for you. – Mark Henderson Dec 1 '11 at 7:55
@Mark Henderson♦, can you respond via moder's tool? – poige Dec 1 '11 at 10:33
up vote 1 down vote accepted

Well, I've found out proper tool to control this cache: sdparm.

It looks like as not having any relation to read-ahead cache. Also, seemingly rare SATA drive is able to unset this bit.

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What is your problem anyway? What do you want to achieve when meddling with this settings? – Sven Feb 1 '11 at 3:38
There's no problem at all, I just paid attention to this very dmesg's message. Also, I thought that turning read cache off in favor of write-cache could be a worth-doing thing if that would increase write cache accordingly (OS caches reading anyway). – poige Feb 1 '11 at 3:49

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