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  1. Cassandra
  2. CASSANDRA-1526

Make cassandra sampling and startup faster

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Details

    • Improvement
    • Status: Resolved
    • Low
    • Resolution: Fixed
    • 0.6.6
    • None
    • None

    Description

      http://wiki.apache.org/cassandra/CassandraHardware makes mention of very large disks I do not see how that would be possible.

      We have a server class system have 4x processors 16GB RAM a 6 DISK RAID5 (yes RAID0 would be faster but still)

      INFO [main] 2010-09-21 12:58:26,348 SSTableReader.java (line 120) Sampling index for /var/lib/cassandra/data/system/LocationInfo-699-Data.db
      ...
      INFO [main] 2010-09-21 13:05:51,333 CassandraDaemon.java (line 124) Binding thrift service to cdbsd07/10.71.71.57:9160
      

      This node has 200GB of data in two column families and the time to sample all tables and startup is 7+ minutes. The logging suggests this process is happening a single SSTable at a time. Additionally the normal system vitals mainly DISK and CPU do not look overtaxed.

      • Since SSTables are immutable is there a way the sampling of the tables could be saved?
      • Could this process be done in parallel for speedup?
      • Can multiple column families be processed at once?

      Unless someone has an insanely powerful disk pack making mention of 2TB limitations seem out of place. Unless my calculations are wrong (which they usually are), I have a pretty decent hardware, and if I had 2 TB of data I would have a 95 minute node start up?

      I hope that maybe sampling multiple ColumnFamilies at once would make nodes of at least a few hundred GB startup reasonably fast.

      Attachments

        1. io.txt
          24 kB
          Edward Capriolo
        2. cpu.txt
          10 kB
          Edward Capriolo
        3. 1526.txt
          4 kB
          Jonathan Ellis
        4. 0.6-0001-Add-AggregateFuture-to-wait-for-a-batch-of-futures-a.patch
          8 kB
          Stu Hood
        5. 0.6-0002-Parallelize-SSTable-open.patch
          10 kB
          Stu Hood
        6. snitcherror.txt
          7 kB
          Edward Capriolo
        7. 1526-v2.txt
          5 kB
          Jonathan Ellis
        8. 1526-v3.txt
          5 kB
          Stu Hood

        Activity

          People

            jbellis Jonathan Ellis
            appodictic Edward Capriolo
            Jonathan Ellis
            Stu Hood
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            Dates

              Created:
              Updated:
              Resolved: