Impact of ext4′s discard option on my SSD

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Solid-state drives (SSDs) are seen as the future of mass storage by many. They are famous for their high performance: extremely low seek times, since there is no head that needs move to a position and then wait for the spinning disk to come around to where it needs to read/write; but also higher throughput of sequential data: My 2,5″ OCZ Vertex LE (100 GB) is rated at 235 MB/s sustained write speed, and read speeds up to 270 MB/s, for example.

There is a caveat though. SSDs are fast at writing, but only when their free space is neatly trimmed. The only component in your software stack that knows which parts of your SSD should be trimmed, is your file system. That is why there is a file system option in ext4 (my current file system of choice), called “discard”.

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