4 ms·

I didn’t know sequential scrub was in this release. Really excited about that one.

• pushpop 7y ago
  Why is that? I’ve not read up on that particular feature.
  • rincebrain 7y ago
    Sequential scrub turns "let's read all the blocks in the order we see them in the metadata" into "let's separate this into a read and a dispatch phase, so we can group things we dispatch into sequential regions and make spinning disks less sad at the amount of random IO needed". It's quite a dramatic improvement for pools on hard drives.
    • pushpop 7y ago
      Oh nice. Thank you for the explanation. Does that have an impact on how long a scrub takes? I’ve always loved the ability to do online scrubs but they can take a long time
      • rincebrain 7y ago
        Very much so. Spinning disks are bad at seeking randomly, and turning lots of random IOs into a smaller number of relatively sequential IOs is a substantial win.