Sun engineer responds to the Backblaze "Petabytes on a budget" design

Post by uibuibk » Thu, Sep 03, 2009, 9:31 PM UTC

sophacles wrote: post #7

Ok I must be missing something. Everyone is knocking this backblaze thing because it doesnt do ZFS or because it is not a "super duper high end san replacement" or because the components are not rated for enterprise level work. It seems to me that a company whose product is personal and small business backups does not need any of those things. They have software to do mirroring. Why would they need any fast network f…

Post by uibuibk » Thu, Sep 03, 2009, 9:35 PM UTC

jacquesm wrote: post #2

That's a pretty weird analysis, comparing a system that is special purpose with a general purpose one. He's concentrating on disk-to-board throughput, but this being network attached storage on a LAN, using the motherboards' single ethernet port the amount of data read or written to those drives per second will never exceed 1 Gbit/second anyway. I agree with the reliability analysis though, backblaze seems to be on f…

Post by mattmcknight » Thu, Sep 03, 2009, 9:58 PM UTC

jacquesm wrote: post #25

notaddicted wrote: post #21

Earlier quoted context omitted.

( ahhh I deleted my post before I saw the response ) From the numbers he cited I got the impression that the drives they are using would fail 3+ times more often than enterprise drives (lower MTTF + speced at low temps). The cost of replacing the drives (even if they are 1/2 the price) would make the system uneconomical. Also: because of their case design (non-hot-swappable) the cost of human replacement is higher to…

I think their use case is sufficiently a-typical to get away with this. They're primarily write-only, only when a customer retrieves their data does stuff get read. If they spin down the drives when the volume is not being accessed the mttf for a single drive goes up a lot, possibly beyond the point where it matters.

Post by rbanffy » Thu, Sep 03, 2009, 10:23 PM UTC

notaddicted wrote: post #21

jacquesm wrote: post #5

Earlier quoted context omitted.

> Given the reliability info he cites, the fact that backblaze is still in business must mean their usage-to-storage ratio is small. No, it probably means that they get their reliability at a different level, such as simply storing the data on a number of machines. Systems like glusterfs make this completely transparant.

( ahhh I deleted my post before I saw the response ) From the numbers he cited I got the impression that the drives they are using would fail 3+ times more often than enterprise drives (lower MTTF + speced at low temps). The cost of replacing the drives (even if they are 1/2 the price) would make the system uneconomical. Also: because of their case design (non-hot-swappable) the cost of human replacement is higher to…

Post by dlsspy » Thu, Sep 03, 2009, 11:01 PM UTC

onedognight wrote: post #33

jacquesm wrote: post #2

That's a pretty weird analysis, comparing a system that is special purpose with a general purpose one. He's concentrating on disk-to-board throughput, but this being network attached storage on a LAN, using the motherboards' single ethernet port the amount of data read or written to those drives per second will never exceed 1 Gbit/second anyway. I agree with the reliability analysis though, backblaze seems to be on f…

Backblaze is making a backup server. They don't need to handle power supply failures. If one goes down, you'll replace it long before someone needs their backup. They don't need to worry about disks failing while writing (zfs and battery backup). Hell they can restart from scratch any one backup that encounters disk failures. They have all the time they want to do a backup.