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https://issues.apache.org/jira/browse/CASSANDRA-15274?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16961436#comment-16961436
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Phil O Conduin commented on CASSANDRA-15274:
--------------------------------------------
Hi Benedict,
Sorry I forgot to come back and update this jira.
Our datafile corruption issues were a problem with the OS wrongly taking one
block belonging to a C* data file thinking it was no longer used and treating
it as a free block that would later be used.
For example:
C* deletes file after compaction, OS collects all blocks which are free now and
sends TRIM command to SSD, but SSD from time to time picks the wrong block, not
the one reported by OS - does the trim - causing zeroized blocks to be seen in
the datafile and later use it for different file.
So the symptom is - we suddenly see 4096 zeroes in the datafile- it means SSD
just trimmed the block, after some time we can see some data written to those
blocks - it means the block is used by other file and therefore gives us a
corrupt file.
We turned off the scheduled TRIM function on the OS and we are no longer
getting corruptions.
This was very difficult to pinpoint.
> Multiple Corrupt datafiles across entire environment
> -----------------------------------------------------
>
> Key: CASSANDRA-15274
> URL: https://issues.apache.org/jira/browse/CASSANDRA-15274
> Project: Cassandra
> Issue Type: Bug
> Components: Local/Compaction
> Reporter: Phil O Conduin
> Priority: Normal
> Labels: impact-high
>
> Cassandra Version: 2.2.13
> PRE-PROD environment.
> * 2 datacenters.
> * 9 physical servers in each datacenter - (_Cisco UCS C220 M4 SFF_)
> * 4 Cassandra instances on each server (cass_a, cass_b, cass_c, cass_d)
> * 72 Cassandra instances across the 2 data centres, 36 in site A, 36 in site
> B.
> We also have 2 Reaper Nodes we use for repair. One reaper node in each
> datacenter each running with its own Cassandra back end in a cluster together.
> OS Details [Red Hat Linux]
> cass_a@x 0 10:53:01 ~ $ uname -a
> Linux x 3.10.0-957.5.1.el7.x86_64 #1 SMP Wed Dec 19 10:46:58 EST 2018 x86_64
> x86_64 x86_64 GNU/Linux
> cass_a@x 0 10:57:31 ~ $ cat /etc/*release
> NAME="Red Hat Enterprise Linux Server"
> VERSION="7.6 (Maipo)"
> ID="rhel"
> Storage Layout
> cass_a@xx 0 10:46:28 ~ $ df -h
> Filesystem Size Used Avail Use% Mounted on
> /dev/mapper/vg01-lv_root 20G 2.2G 18G 11% /
> devtmpfs 63G 0 63G 0% /dev
> tmpfs 63G 0 63G 0% /dev/shm
> tmpfs 63G 4.1G 59G 7% /run
> tmpfs 63G 0 63G 0% /sys/fs/cgroup
> >> 4 cassandra instances
> /dev/sdd 1.5T 802G 688G 54% /data/ssd4
> /dev/sda 1.5T 798G 692G 54% /data/ssd1
> /dev/sdb 1.5T 681G 810G 46% /data/ssd2
> /dev/sdc 1.5T 558G 932G 38% /data/ssd3
> Cassandra load is about 200GB and the rest of the space is snapshots
> CPU
> cass_a@x 127 10:58:47 ~ $ lscpu | grep -E '^Thread|^Core|^Socket|^CPU\('
> CPU(s): 64
> Thread(s) per core: 2
> Core(s) per socket: 16
> Socket(s): 2
> *Description of problem:*
> During repair of the cluster, we are seeing multiple corruptions in the log
> files on a lot of instances. There seems to be no pattern to the corruption.
> It seems that the repair job is finding all the corrupted files for us. The
> repair will hang on the node where the corrupted file is found. To fix this
> we remove/rename the datafile and bounce the Cassandra instance. Our
> hardware/OS team have stated there is no problem on their side. I do not
> believe it the repair causing the corruption.
>
> So let me give you an example of a corrupted file and maybe someone might be
> able to work through it with me?
> When this corrupted file was reported in the log it looks like it was the
> repair that found it.
> $ journalctl -u cassmeta-cass_b.service --since "2019-08-07 22:25:00" --until
> "2019-08-07 22:45:00"
> Aug 07 22:30:33 cassandra[34611]: INFO 21:30:33 Writing
> Memtable-compactions_in_progress@830377457(0.008KiB serialized bytes, 1 ops,
> 0%/0% of on/off-heap limit)
> Aug 07 22:30:33 cassandra[34611]: ERROR 21:30:33 Failed creating a merkle
> tree for [repair #9587a200-b95a-11e9-8920-9f72868b8375 on KeyspaceMetadata/x,
> (-1476350953672479093,-1474461
> Aug 07 22:30:33 cassandra[34611]: ERROR 21:30:33 Exception in thread
> Thread[ValidationExecutor:825,1,main]
> Aug 07 22:30:33 cassandra[34611]: org.apache.cassandra.io.FSReadError:
> org.apache.cassandra.io.sstable.CorruptSSTableException: Corrupted:
> /x/ssd2/data/KeyspaceMetadata/x-1e453cb0
> Aug 07 22:30:33 cassandra[34611]: at
> org.apache.cassandra.io.util.RandomAccessReader.readBytes(RandomAccessReader.java:365)
> ~[apache-cassandra-2.2.13.jar:2.2.13]
> Aug 07 22:30:33 cassandra[34611]: at
> org.apache.cassandra.utils.ByteBufferUtil.read(ByteBufferUtil.java:361)
> ~[apache-cassandra-2.2.13.jar:2.2.13]
> Aug 07 22:30:33 cassandra[34611]: at
> org.apache.cassandra.utils.ByteBufferUtil.readWithShortLength(ByteBufferUtil.java:340)
> ~[apache-cassandra-2.2.13.jar:2.2.13]
> Aug 07 22:30:33 cassandra[34611]: at
> org.apache.cassandra.db.composites.AbstractCType$Serializer.deserialize(AbstractCType.java:382)
> ~[apache-cassandra-2.2.13.jar:2.2.13]
> Aug 07 22:30:33 cassandra[34611]: at
> org.apache.cassandra.db.composites.AbstractCType$Serializer.deserialize(AbstractCType.java:366)
> ~[apache-cassandra-2.2.13.jar:2.2.13]
> Aug 07 22:30:33 cassandra[34611]: at
> org.apache.cassandra.db.OnDiskAtom$Serializer.deserializeFromSSTable(OnDiskAtom.java:81)
> ~[apache-cassandra-2.2.13.jar:2.2.13]
> Aug 07 22:30:33 cassandra[34611]: at
> org.apache.cassandra.db.AbstractCell$1.computeNext(AbstractCell.java:52)
> ~[apache-cassandra-2.2.13.jar:2.2.13]
> Aug 07 22:30:33 cassandra[34611]: at
> org.apache.cassandra.db.AbstractCell$1.computeNext(AbstractCell.java:46)
> ~[apache-cassandra-2.2.13.jar:2.2.13]
> Aug 07 22:30:33 cassandra[34611]: at
> com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:143)
> ~[guava-16.0.jar:na]
> Aug 07 22:30:33 cassandra[34611]: at
> com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:138)
> ~[guava-16.0.jar:na]
> Aug 07 22:30:33 cassandra[34611]: at
> org.apache.cassandra.io.sstable.SSTableIdentityIterator.hasNext(SSTableIdentityIterator.java:169)
> ~[apache-cassandra-2.2.13.jar:2.2.13]
> Aug 07 22:30:33 cassandra[34611]: at
> org.apache.cassandra.utils.MergeIterator$OneToOne.computeNext(MergeIterator.java:202)
> ~[apache-cassandra-2.2.13.jar:2.2.13]
> Aug 07 22:30:33 cassandra[34611]: at
> com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:143)
> ~[guava-16.0.jar:na]
> Aug 07 22:30:33 cassandra[34611]: at
> com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:138)
> ~[guava-16.0.jar:na]
> Aug 07 22:30:33 cassandra[34611]: at
> com.google.common.collect.Iterators$7.computeNext(Iterators.java:645)
> ~[guava-16.0.jar:na]
> Aug 07 22:30:33 cassandra[34611]: at
> com.google.common.collect.AbstractIterator.tryToComputeNext(AbstractIterator.java:143)
> ~[guava-16.0.jar:na]
> Aug 07 22:30:33 cassandra[34611]: at
> com.google.common.collect.AbstractIterator.hasNext(AbstractIterator.java:138)
> ~[guava-16.0.jar:na]
> Aug 07 22:30:33 cassandra[34611]: at
> org.apache.cassandra.db.ColumnIndex$Builder.buildForCompaction(ColumnIndex.java:174)
> ~[apache-cassandra-2.2.13.jar:2.2.13]
> Aug 07 22:30:33 cassandra[34611]: at
> org.apache.cassandra.db.compaction.LazilyCompactedRow.update(LazilyCompactedRow.java:187)
> ~[apache-cassandra-2.2.13.jar:2.2.13]
> Aug 07 22:30:33 cassandra[34611]: at
> org.apache.cassandra.repair.Validator.rowHash(Validator.java:201)
> ~[apache-cassandra-2.2.13.jar:2.2.13]
> Aug 07 22:30:33 cassandra[34611]: at
> org.apache.cassandra.repair.Validator.add(Validator.java:150)
> ~[apache-cassandra-2.2.13.jar:2.2.13]
> Aug 07 22:30:33 cassandra[34611]: at
> org.apache.cassandra.db.compaction.CompactionManager.doValidationCompaction(CompactionManager.java:1166)
> ~[apache-cassandra-2.2.13.jar:2.2.13]
> Aug 07 22:30:33 cassandra[34611]: at
> org.apache.cassandra.db.compaction.CompactionManager.access$600(CompactionManager.java:76)
> ~[apache-cassandra-2.2.13.jar:2.2.13]
> Aug 07 22:30:33 cassandra[34611]: at
> org.apache.cassandra.db.compaction.CompactionManager$10.call(CompactionManager.java:736)
> ~[apache-cassandra-2.2.13.jar:2.2.13]
> Aug 07 22:30:33 cassandra[34611]: at
> java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[na:1.8.0_172]
> Aug 07 22:30:33 cassandra[34611]: at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
> ~[na:1.8.0_172]
> Aug 07 22:30:33 cassandra[34611]: at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
> [na:1.8.0_172]
> Aug 07 22:30:33 cassandra[34611]: at java.lang.Thread.run(Thread.java:748)
> [na:1.8.0_172]
> Aug 07 22:30:33 cassandra[34611]: Caused by:
> org.apache.cassandra.io.sstable.CorruptSSTableException: Corrupted:
> /data/ssd2/data/KeyspaceMetadata/x-x/l
> Aug 07 22:30:33 cassandra[34611]: at
> org.apache.cassandra.io.compress.CompressedRandomAccessReader.reBufferMmap(CompressedRandomAccessReader.java:216)
> ~[apache-cassandra-2.2.13.jar:2.2.13]
> Aug 07 22:30:33 cassandra[34611]: at
> org.apache.cassandra.io.compress.CompressedRandomAccessReader.reBuffer(CompressedRandomAccessReader.java:226)
> ~[apache-cassandra-2.2.13.jar:2.2.13]
> Aug 07 22:30:33 cassandra[34611]: at
> org.apache.cassandra.io.compress.CompressedThrottledReader.reBuffer(CompressedThrottledReader.java:42)
> ~[apache-cassandra-2.2.13.jar:2.2.13]
> Aug 07 22:30:33 cassandra[34611]: at
> org.apache.cassandra.io.util.RandomAccessReader.readBytes(RandomAccessReader.java:352)
> ~[apache-cassandra-2.2.13.jar:2.2.13]
> Aug 07 22:30:33 cassandra[34611]: ... 27 common frames omitted
> Aug 07 22:30:33 cassandra[34611]: Caused by:
> org.apache.cassandra.io.compress.CorruptBlockException:
> (/data/ssd2/data/KeyspaceMetadata/x-x/lb-26203-big
> Aug 07 22:30:33 cassandra[34611]: at
> org.apache.cassandra.io.compress.CompressedRandomAccessReader.reBufferMmap(CompressedRandomAccessReader.java:185)
> ~[apache-cassandra-2.2.13.jar:2.2.13]
> Aug 07 22:30:33 cassandra[34611]: ... 30 common frames omitted
> Aug 07 22:30:33 cassandra[34611]: INFO 21:30:33 Not a global repair, will
> not do anticompaction
> Aug 07 22:30:33 cassandra[34611]: ERROR 21:30:33 Stopping gossiper
> Aug 07 22:30:33 cassandra[34611]: WARN 21:30:33 Stopping gossip by operator
> request
> Aug 07 22:30:33 cassandra[34611]: INFO 21:30:33 Announcing shutdown
> Aug 07 22:30:33 cassandra[34611]: INFO 21:30:33 Node
> /[10.2.57.37|http://10.2.57.37/]state jump to shutdown
> So I went to the file system to see when this corrupt file was created and it
> was created on July 30th at 15.55
> root@x 0 01:14:03 ~ # ls -l
> /data/ssd2/data/KeyspaceMetadata/x-x/lb-26203-big-Data.db
> -rw-r--r-- 1 cass_b cass_b 3182243670 Jul 30 15:55
> /data/ssd2/data/KeyspaceMetadata/x-x/lb-26203-big-Data.db
> So I checked /var/log/messages for errors around that time
> The only thing that stands out to me is the message "Cannot perform a full
> major compaction as repaired and unrepaired sstables cannot be compacted
> together", I'm not sure if this would be an issue though and cause corruption.
> Jul 30 15:55:06 x systemd: Created slice User Slice of root.
> Jul 30 15:55:06 x systemd: Started Session c165280 of user root.
> Jul 30 15:55:06 x audispd: node=x. type=USER_START
> msg=audit(1564498506.021:457933): pid=17533 uid=0 auid=4294967295
> ses=4294967295 msg='op=PAM:session_open
> grantors=pam_keyinit,pam_limits,pam_keyinit,pam_limits,pam_tty_audit,pam_systemd,pam_unix
> acct="root" exe="/usr/bin/sudo" hostname=? addr=? terminal=? res=success'
> Jul 30 15:55:06 x systemd: Removed slice User Slice of root.
> Jul 30 15:55:14 x tag_audit_log: type=USER_CMD
> msg=audit(1564498506.013:457932): pid=17533 uid=509 auid=4294967295
> ses=4294967295 msg='cwd="/"
> cmd=2F7573722F7362696E2F69706D692D73656E736F7273202D2D71756965742D6361636865202D2D7364722D63616368652D7265637265617465202D2D696E746572707265742D6F656D2D64617461202D2D6F75747075742D73656E736F722D7374617465202D2D69676E6F72652D6E6F742D617661696C61626C652D73656E736F7273202D2D6F75747075742D73656E736F722D7468726573686F6C6473
> terminal=? res=success'
> Jul 30 15:55:14 x tag_audit_log: type=USER_START
> msg=audit(1564498506.021:457933): pid=17533 uid=0 auid=4294967295
> ses=4294967295 msg='op=PAM:session_open
> grantors=pam_keyinit,pam_limits,pam_keyinit,pam_limits,pam_tty_audit,pam_systemd,pam_unix
> acct="root" exe="/usr/bin/sudo" hostname=? addr=? terminal=? res=success'
> Jul 30 15:55:19 x cassandra: INFO 14:55:19 Writing
> Memtable-compactions_in_progress@1462227999(0.008KiB serialized bytes, 1 ops,
> 0%/0% of on/off-heap limit)
> Jul 30 15:55:19 x cassandra: INFO 14:55:19 Cannot perform a full major
> compaction as repaired and unrepaired sstables cannot be compacted together.
> These two set of sstables will be compacted separately.
> Jul 30 15:55:19 x cassandra: INFO 14:55:19 Writing
> Memtable-compactions_in_progress@1198535528(1.002KiB serialized bytes, 57
> ops, 0%/0% of on/off-heap limit)
> Jul 30 15:55:20 x cassandra: INFO 14:55:20 Writing
> Memtable-compactions_in_progress@2039409834(0.008KiB serialized bytes, 1 ops,
> 0%/0% of on/off-heap limit)
> Jul 30 15:55:24 x audispd: node=x. type=USER_LOGOUT
> msg=audit(1564498524.409:457934): pid=46620 uid=0 auid=464400029 ses=2747
> msg='op=login id=464400029 exe="/usr/sbin/sshd" hostname=? addr=?
> terminal=/dev/pts/0 res=success'
> Jul 30 15:55:24 x audispd: node=x. type=USER_LOGOUT
> msg=audit(1564498524.409:457935): pid=4878 uid=0 auid=464400029 ses=2749
> msg='op=login id=464400029 exe="/usr/sbin/sshd" hostname=? addr=?
> terminal=/dev/pts/1 res=success'
> Jul 30 15:55:57 x systemd: Created slice User Slice of root.
> Jul 30 15:55:57 x systemd: Started Session c165288 of user root.
> Jul 30 15:55:57 x audispd: node=x. type=USER_START
> msg=audit(1564498557.294:457958): pid=19687 uid=0 auid=4294967295
> ses=4294967295 msg='op=PAM:session_open
> grantors=pam_keyinit,pam_limits,pam_keyinit,pam_limits,pam_tty_audit,pam_systemd,pam_unix
> acct="root" exe="/usr/bin/sudo" hostname=? addr=? terminal=? res=success'
> Jul 30 15:55:57 x audispd: node=x. type=USER_START
> msg=audit(1564498557.298:457959): pid=19690 uid=0 auid=4294967295
> ses=4294967295 msg='op=PAM:session_open
> grantors=pam_keyinit,pam_systemd,pam_keyinit,pam_limits,pam_unix
> acct="cass_b" exe="/usr/sbin/runuser" hostname=? addr=? terminal=?
> res=success'
> Jul 30 15:55:58 x systemd: Removed slice User Slice of root.
> Jul 30 15:56:02 x cassandra: INFO 14:56:02 Writing
> Memtable-compactions_in_progress@1532791194(0.008KiB serialized bytes, 1 ops,
> 0%/0% of on/off-heap limit)
> Jul 30 15:56:02 x cassandra: INFO 14:56:02 Cannot perform a full major
> compaction as repaired and unrepaired sstables cannot be compacted together.
> These two set of sstables will be compacted separately.
> Jul 30 15:56:02 x cassandra: INFO 14:56:02 Writing
> Memtable-compactions_in_progress@1455399453(0.281KiB serialized bytes, 16
> ops, 0%/0% of on/off-heap limit)
> Jul 30 15:56:04 x tag_audit_log: type=USER_CMD
> msg=audit(1564498555.190:457951): pid=19294 uid=509 auid=4294967295
> ses=4294967295 msg='cwd="/"
> cmd=72756E75736572202D73202F62696E2F62617368202D6C20636173735F62202D632063617373616E6472612D6D6574612F63617373616E6472612F62696E2F6E6F6465746F6F6C2074707374617473
> terminal=? res=success'
> We have checked a number of other things like NTP setting etc but nothing is
> telling us what could cause so many corruptions across the entire cluster.
> Things were healthy with this cluster for months, the only thing I can think
> is that we started loading data from a load of 20GB per instance up to 200GB
> where it sits now, maybe this just highlighted the issue.
> Compaction and Compression on Keyspace CL's [mixture]
> All CF's are using compression.
> AND compaction = {'min_threshold': '4', 'class':
> 'org.apache.cassandra.db.compaction.*SizeTieredCompactionStrategy*',
> 'max_threshold': '32'}
> AND compression = {'sstable_compression':
> 'org.apache.cassandra.io.compress.*SnappyCompressor*'}
> AND compaction = {'min_threshold': '4', 'class':
> 'org.apache.cassandra.db.compaction.*SizeTieredCompactionStrategy*',
> 'max_threshold': '32'}
> AND compression = {'sstable_compression':
> 'org.apache.cassandra.io.compress.*LZ4Compressor*'}
> AND compaction = {'class':
> 'org.apache.cassandra.db.compaction.*LeveledCompactionStrategy*'}
> AND compression = {'sstable_compression':
> 'org.apache.cassandra.io.compress.*SnappyCompressor*'}
> --We are also using internode network compression:
> internode_compression: all
>
>
> Please tell me whatever you need to help me debug this issue.
>
>
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