3 ms·
> Durability: RAMCloud replicates all data on nonvolatile secondary storage such as disk or flash, so no data is lost if servers crash or the power fails. How
by byte1918 8y ago
> Durability: RAMCloud replicates all data on nonvolatile secondary storage such as disk or flash, so no data is lost if servers crash or the power fails.
How does this work if someone is doing multiple sequential writes? Doesn't backup-ing to disk take a lot longer than writing to _RAM_ meaning some writes could get lost?
- vbezhenar 8y agoYou can distribute writes over multiple disks.
- byte1918 8y agoOut of pure curiosity but wouldn't the number of disks required to guarantee 100% write-backup at 100% peak times be pretty big? A quick search says HDD is ~200 times slower than RAM (on average, consumer grade).
- ddorian43 8y agoYou should see sequential write speed. Its probably writing a log + checkpointing.
- vbezhenar 8y agoI guess it should be big indeed. To somewhat reduce its number, you can buffer writes in another DRAM if those peaks are expected to be short. You can overprovision if you have multiple clients and expecting that they won't peak write together for a prolonged periods of time.