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Joined 3 years ago
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Cake day: June 22nd, 2023

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  • While I don’t exactly intend to run RAID, I ended up choosing nas drives for the 24/7 intended usage,

    The purpose of a NAS drive is to be LESS reliable than a regular drive, not more reliable. Explanation: if a regular drive gets a read error on a block, it will retry for quite a while before giving up. The host, meanwhile, has to wait for the data to be retrieved if the retries work. That’s all it can really do, wait and hope. Meanwhile, the waiting slows the application down.

    A NAS drive instead will fail once or twice, then give up immediately, since it knows that it’s in a RAID system and that the data is also present on other disks. The RAID then puts the data together from the other drives and gets it to the host, logging the error. It will also hopefully mark the bad block on the drive with the read failure, and rewrite the recovered data to a spare sector. So this is faster than all the retries even though the drive that had the bad block gives up on it rather than attempting recovery by repeated reads.

    So if you buy NAS drives, put them in a RAID.

    Drives are currently around 2x as expensive as a year or so ago but they are available if you can afford them. I guess that’s better than shortages where they’re hard to find even if you can pay. We’ve had that before too.

    I like to think the current situation will settle out. Who knows though. Drive space is still way less expensive than in 2010 or anything like that.