FLASH drives do need a scheduler policy [LWN.net]

FLASH drives do need a scheduler policy

Posted Oct 1, 2004 16:51 UTC (Fri) by BrucePerens (subscriber, #2510)
In reply to: FLASH drives do need a scheduler policy by axboe
Parent article: Modular, switchable I/O schedulers

Jens,

Yes, that's true. However, it can be fixed, if the filesystem communicates either a write barrier (write this block before any blocks I send down after it) or ordering information (write block X before block Y, order of block Z doesn't matter). Once it is so easy to work on I/O scheduling, the need for this will become so evident that there is no question that it will be done.

Bruce

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FLASH drives do need a scheduler policy

Posted Oct 3, 2004 9:48 UTC (Sun) by axboe (subscriber, #904) [Link]

Bruce,

We already have write barriers, and it doesn't solve the entire problem. It will make any given fs more flash friendly indeed, but it's still quite a bit away from a fs specifically designed to minimize drive wear.

Your last sentence doesn't make sense.

Jens

FLASH drives do need a scheduler policy

Posted Oct 3, 2004 12:06 UTC (Sun) by BrucePerens (subscriber, #2510) [Link]

Jens,

OK. I think one of the BSDs goes a bit further than write barriers in communicating time information. But I see your point that this can not go all of the way in reducing FLASH wear.

Thanks

Bruce