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Datacenters still are relying on spinning storage and pretty much everywhere I read will continue to for the foreseeable future. I'm curious what the other fac

Datacenters still are relying on spinning storage and pretty much everywhere I read will continue to for the foreseeable future. I'm curious what the other factors are beyond just the cost per TB/PB in each rack. Like reliability over very long time scales... beyond the cost factor and into archival territory. Or in an emergency or destructive scenario (i.e. do platter drives fair better in a fire than SSDs)

loeg 9y ago
The only reason they're using spinning storage is it's cheaper. I work for a big storage vendor. We would switch to all flash tomorrow if it were equal or lower $/GB (already has better performance and density).
- rasz 9y ago
  no you wouldnt, Flash is useless for cold and very hot storage, anything that is not touched for more than 6 months, or will be rewritten more than ~2000 times in under a year is either impossible or uneconomical with solid state.
  - loeg 9y ago
    I'm not talking about the market segments where tape or RAM dominate (and would continue to dominate). I think the use cases you are imagining for spinning rust are a tiny portion of the market for storage, or simply do not exist. For example: It's hard to actually rewrite spinning rust 2000 times a year. That's exceeding 100% utilization with completely optimal sequential write pattern on 7200 RPM drives. Say you can write 200 MB/s continuously[0]. That's about 6 PB/year. With a 6 TB harddrive, that's only 1000 full overwrites a year. Maybe 10k or 15k RPM drives can overwrite 2000 times a year, but those have vastly higher cost than 7200 RPM drives. At some point, you just overprovision the flash enough to bring the number of required overwrites down, and it's still cheaper than 10-15k RPM drives. [0]: Approximately average for enterprise drives: http://www.tomsitpro.com/articles/enterprise-hdd-testing,2-896.html http://www.tomsitpro.com/articles/enterprise-hdd-testing,2-8...
    - davrosthedalek 9y ago
      Wasn't there some speculation that Glacier and co actually use optical media, not tapes, for their storage? Does anybody know?
      - loeg 9y ago
        I'd heard that speculation too, but do not have any actual knowledge of what Glacier uses. I don't deal with truly cold, offline storage at all.

loeg 9y ago

The only reason they're using spinning storage is it's cheaper. I work for a big storage vendor. We would switch to all flash tomorrow if it were equal or lower $/GB (already has better performance and density).

rasz 9y ago
no you wouldnt, Flash is useless for cold and very hot storage, anything that is not touched for more than 6 months, or will be rewritten more than ~2000 times in under a year is either impossible or uneconomical with solid state.
- loeg 9y ago
  I'm not talking about the market segments where tape or RAM dominate (and would continue to dominate). I think the use cases you are imagining for spinning rust are a tiny portion of the market for storage, or simply do not exist. For example: It's hard to actually rewrite spinning rust 2000 times a year. That's exceeding 100% utilization with completely optimal sequential write pattern on 7200 RPM drives. Say you can write 200 MB/s continuously[0]. That's about 6 PB/year. With a 6 TB harddrive, that's only 1000 full overwrites a year. Maybe 10k or 15k RPM drives can overwrite 2000 times a year, but those have vastly higher cost than 7200 RPM drives. At some point, you just overprovision the flash enough to bring the number of required overwrites down, and it's still cheaper than 10-15k RPM drives. [0]: Approximately average for enterprise drives: http://www.tomsitpro.com/articles/enterprise-hdd-testing,2-896.html http://www.tomsitpro.com/articles/enterprise-hdd-testing,2-8...
  - davrosthedalek 9y ago
    Wasn't there some speculation that Glacier and co actually use optical media, not tapes, for their storage? Does anybody know?
    - loeg 9y ago
      I'd heard that speculation too, but do not have any actual knowledge of what Glacier uses. I don't deal with truly cold, offline storage at all.