Hi all, I have 5 nodes in my C* cluster, and each node has the same configuration file(Cassandra-env.sh: MAX_HEAP_SIZE="32G" and HEAP_NEWSIZE="8G"), and My Cassandra version is 2.1.1. Now I want to export all data of one table, i am using select * from tablename, and set the bStatement.setFetchSize(10000); When exporting the data, I check the status of the C* cluster, I found the following: Status=Up/Down |/ State=Normal/Leaving/Joining/Moving -- Address Load Tokens Owns Host ID Rack UN 134.13.13.36 15.82 GB 256 ? 67aecea2-00f5-4001-ba4c-dc6138edaaa0 rack1 UN 134.13.13.37 20.25 GB 256 ? a8c0ec24-6e48-4082-be53-32a971a4aaaa rack1 DN 134.13.13.33 18.36 GB 256 ? d93f8201-a3a7-404a-8dd6-164ddbfeaaa7 rack1 UN 134.13.13.34 16.9 GB 256 ? 6880cf40-0b73-4bbc-a0a5-7799a983aaab rack1 UN 134.13.13.35 19.78 GB 256 ? 5658ae76-40a0-441f-908e-9d11ab2baaad rack1 The Cassandra jstat information on node 134.13.13.33 is following. I can see that Cassandra does not use S1, and it does not do the young GC, instead, it just do Full GC, and it do so many Full GC and so long, so C* cluster think it is Down. The node 134.13.13.33 can only work normally after startup for a while, after many times to do Full GC, it is Down and cannot finish the Full GC progress and crash at the end. [cache@cache02 caslog]$ jstat -gcutil 62335 4000 2000 S0 S1 E O P YGC YGCT FGC FGCT GCT 86.49 0.00 100.00 98.02 72.54 19 38.236 3 0.863 39.099 86.49 0.00 100.00 98.02 72.54 19 38.236 4 0.863 39.099 86.49 0.00 100.00 98.02 72.54 19 38.236 4 0.863 39.099 86.49 0.00 100.00 98.02 72.54 19 38.236 4 0.863 39.099 86.49 0.00 100.00 98.02 72.54 19 38.236 4 0.863 39.099 86.49 0.00 100.00 98.02 72.54 19 38.236 4 0.863 39.099 86.49 0.00 100.00 98.02 72.54 19 38.236 4 0.863 39.099 86.49 0.00 100.00 98.02 72.54 19 38.236 4 0.863 39.099 86.49 0.00 100.00 98.02 72.54 19 38.236 4 0.863 39.099 86.49 0.00 100.00 98.02 72.54 19 38.236 4 0.863 39.099 86.49 0.00 100.00 98.02 72.54 19 38.236 4 0.863 39.099 86.49 0.00 100.00 98.02 72.54 19 38.236 4 0.863 39.099 86.49 0.00 100.00 98.02 72.54 19 38.236 4 0.863 39.099 86.49 0.00 100.00 98.02 72.54 19 38.236 4 0.863 39.099 86.49 0.00 100.00 98.02 72.54 19 38.236 4 0.863 39.099 86.49 0.00 100.00 98.02 72.54 19 38.236 4 0.863 39.099 86.49 0.00 100.00 98.02 72.52 19 38.236 4 0.863 39.099 86.49 0.00 100.00 98.02 72.52 19 38.236 4 0.863 39.099 86.49 0.00 100.00 98.02 72.52 19 38.236 4 0.863 39.099 0.00 0.00 41.13 100.00 72.52 19 38.236 4 71.671 109.906 0.00 0.00 41.13 100.00 72.52 19 38.236 4 71.671 109.906 0.00 0.00 41.13 100.00 72.52 19 38.236 4 71.671 109.906 0.00 0.00 41.13 100.00 72.52 19 38.236 4 71.671 109.906 0.00 0.00 77.65 100.00 60.03 19 38.236 5 71.671 109.906 20.27 0.00 100.00 100.00 60.27 19 38.236 5 73.905 112.141 58.59 0.00 100.00 100.00 60.30 19 38.236 5 73.905 112.141 98.19 0.00 100.00 100.00 60.30 19 38.236 5 73.905 112.141 100.00 0.00 100.00 100.00 60.30 19 38.236 5 73.905 112.141 100.00 0.00 100.00 100.00 60.30 19 38.236 5 73.905 112.141 100.00 0.00 100.00 100.00 60.30 19 38.236 5 73.905 112.141 100.00 0.00 100.00 100.00 60.30 19 38.236 5 73.905 112.141 100.00 0.00 100.00 100.00 60.30 19 38.236 6 73.905 112.141 100.00 0.00 100.00 100.00 60.30 19 38.236 6 73.905 112.141 100.00 0.00 100.00 100.00 60.30 19 38.236 6 73.905 112.141 100.00 0.00 100.00 100.00 60.30 19 38.236 6 73.905 112.141 100.00 0.00 100.00 100.00 60.30 19 38.236 6 73.905 112.141 100.00 0.00 100.00 100.00 60.30 19 38.236 6 73.905 112.141 100.00 0.00 100.00 100.00 60.30 19 38.236 6 73.905 112.141 100.00 0.00 100.00 100.00 60.30 19 38.236 6 73.905 112.141 100.00 0.00 100.00 100.00 60.30 19 38.236 6 73.905 112.141 100.00 0.00 100.00 100.00 60.30 19 38.236 6 73.905 112.141 100.00 0.00 100.00 100.00 60.30 19 38.236 6 73.905 112.141 100.00 0.00 100.00 100.00 60.30 19 38.236 6 73.905 112.141 100.00 0.00 100.00 100.00 60.30 19 38.236 6 73.905 112.141 100.00 0.00 100.00 100.00 60.30 19 38.236 6 73.905 112.141 100.00 0.00 100.00 100.00 60.30 19 38.236 6 73.905 112.141 100.00 0.00 100.00 100.00 60.30 19 38.236 6 73.905 112.141 100.00 0.00 100.00 100.00 60.30 19 38.236 6 73.905 112.141 0.00 0.00 78.90 100.00 60.30 19 38.236 6 141.773 180.008 0.00 0.00 78.90 100.00 60.30 19 38.236 6 141.773 180.008 0.00 0.00 78.90 100.00 60.30 19 38.236 6 141.773 180.008
Other Cassandra jstat information of other node of this C* cluster is following, I think it is normal because it can do young GC so many times then do Full GC: [cache@cache06 ~]$ jstat -gcutil 32060 4000 2000 S0 S1 E O P YGC YGCT FGC FGCT GCT 0.00 100.00 26.53 59.08 60.02 609 140.372 12 89.422 229.794 0.00 100.00 33.48 61.20 60.02 611 140.834 12 89.422 230.257 0.00 100.00 50.18 63.71 60.02 613 141.384 12 89.422 230.807 11.65 0.00 83.51 66.31 60.02 616 141.723 12 89.422 231.146 100.00 100.00 100.00 68.40 60.02 619 142.167 12 89.422 231.590 0.00 100.00 13.15 71.60 60.02 621 143.195 12 89.422 232.618 0.00 100.00 27.69 73.89 60.02 623 143.679 12 89.422 233.102 100.00 0.00 71.57 74.60 60.02 624 143.772 12 89.422 233.194 0.00 94.92 88.87 74.97 60.02 625 143.838 12 89.422 233.260 100.00 100.00 100.00 76.37 60.02 627 143.942 13 89.577 233.519 0.00 100.00 78.16 76.32 60.02 627 144.027 14 90.273 234.300 0.00 100.00 31.22 58.51 60.02 629 144.425 14 90.273 234.698 100.00 0.00 27.90 44.76 60.02 632 145.104 14 90.273 235.377 100.00 0.00 32.10 29.26 60.02 634 145.254 14 90.273 235.527 83.50 0.00 65.04 27.60 59.78 636 145.395 14 90.273 235.669 100.00 0.00 72.60 28.20 59.78 638 145.534 14 90.273 235.807 0.00 100.00 5.97 28.73 59.78 641 145.703 14 90.273 235.976 0.00 76.34 34.28 29.32 59.78 643 145.877 14 90.273 236.150 0.00 97.42 91.21 29.50 59.79 645 145.971 14 90.273 236.244 0.00 100.00 94.70 29.72 59.79 647 146.070 14 90.273 236.343 78.65 0.00 46.82 30.19 59.79 650 146.201 14 90.273 236.475 59.25 0.00 49.98 30.19 59.79 652 146.267 14 90.273 236.540