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Laurence Perkins wrote: |
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> With regard to SMR drives, note that there are three basic types: |
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> |
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> Some completely hide the fact that they are SMR. These suck, hands down. Performance is unpredictable and random. |
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> Some at least advertise that they're SMR, and expose basic counters about where they are in their maintenance cycles. These still suck, but at least you can kind of predict when they're about to get really slow. |
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> |
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> The best ones actually advertise what the shingled ranges are, at which point a new enough kernel and filesystem can keep the writes to those ranges as sequential as possible, and you can use the big, cheap drives with very little performance loss. |
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> |
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> There are a couple articles explaining how to determine what you've got and optimize it. I don't have my bookmarks to hand, but it was in a discussion on this list a few months ago. |
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> |
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> LMP |
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> |
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That's some new info. I tend to follow threads, even started one ages |
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ago about my hard drive doing a bumpy thing for a long time after I |
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updated my backups. Rich plus others informed me I unknowingly bought a |
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SMR drive. I think mine has about a 15 or 20GB CMR section. I've |
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noticed if my updates go to about that much or more, it gets slow. |
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Either way, it does the bumpy thing for a good while after my backups |
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are done and I've unmounted the drive. I just let it sit there until it |
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gets done. If I don't, it just slows down faster the next time because |
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it starts out behind on moving the files from CMR to SMR and doing its |
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rewrite thing. |
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|
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My biggest point for the OP, look at its use and pick what works as |
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expected. I've read, and Wol seems to confirm this, that RAID and SMR |
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do not go together well. I've read some have hosed RAID thingys when |
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they put in a SMR drive and didn't know it. |
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The biggest problem I have is when they don't let us know when a drive |
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is SMR. I don't like a company that sells me something that isn't as |
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good without telling me. It sort of rubs me the wrong way. |
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To the OP tho, research first, then buy. Know what you getting and that |
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it will work for your needs. As I said, for the most part, my backup |
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drive being SMR is mostly a little annoying. It does work. I just |
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won't do it again tho. |
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|
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Dale |
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|
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:-) :-) |
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