Leveldb segfault during Riak startup

Matthew Von-Maszewski matthewv at basho.com
Tue Jan 19 16:05:33 EST 2016


riak-users,

Antti's issues has been addressed via a correction to leveldb.  Upcoming releases of Riak will of course contain this correction.  The fix for Riak 2.x is tagged 2.0.11 at github.com/basho/leveldb.  The same fix is also part of the leveldb "develop" branch.

Bug discussion is here:  https://github.com/basho/leveldb/wiki/mv-startup-segfault

Matthew


> On Jan 1, 2016, at 3:25 PM, Antti Kuusela <antti.kuusela at firstbeat.com> wrote:
> 
> Hi Matthew,
> 
> This phenomenon started after upgrade to 2.1.2. I downgraded the servers to 2.1.1, now waiting to see if it makes a difference.
> 
> I installed the binary packages from Basho repo.
> 
> 
> 
> ________________________________________
> From: Matthew Von-Maszewski <matthewv at basho.com>
> Sent: 31 December 2015 18:25
> To: Antti Kuusela
> Cc: Luke Bakken; riak-users
> Subject: Re: Leveldb segfault during Riak startup
> 
> I also failed to ask two basic questions:
> 
> 1.  did this failure start after your upgrade to 2.1.3, or happen prior to upgrade also?
> 
> 2.  did you use a Basho package for Centos 7, or did you build from source code?
> 
> Matthew
> 
> 
>> On Dec 31, 2015, at 6:06 AM, Antti Kuusela <antti.kuusela at firstbeat.fi> wrote:
>> 
>> Hi Luke,
>> 
>> We erased the btrfs file system, replaced it with xfs on lvm with thinly-provisioned volumes and continued testing with a new database from scratch. The same problem continues, though. From /var/log/messages:
>> 
>> Dec 31 03:35:31 storage5 riak[66419]: Starting up
>> Dec 31 03:35:45 storage5 kernel: traps: beam.smp[66731] general protection ip:7f02280b3f16 sp:7f0197ad8dd0 error:0 in eleveldb.so[7f0228066000+93000]
>> Dec 31 03:35:46 storage5 run_erl[66417]: Erlang closed the connection.
>> 
>> 
>> 
>> 18.12.2015, 16:45, Luke Bakken kirjoitti:
>>> Hi Antti,
>>> 
>>> Riak is not tested on btrfs and the file system is not officially
>>> supported. We recommend ext4 or xfs for Linux. ZFS is an option on
>>> Solaris derivatives and FreeBSD.
>>> 
>>> --
>>> Luke Bakken
>>> Engineer
>>> lbakken at basho.com
>>> 
>>> 
>>> On Fri, Dec 18, 2015 at 6:14 AM, Antti Kuusela
>>> <antti.kuusela at firstbeat.fi> wrote:
>>>> Hi,
>>>> 
>>>> I have been testing Riak and Riak CS as a possible solution for our future
>>>> storage needs. I have a five server cluster running Centos 7. Riak version
>>>> is 2.1.3 (first installed as 2.1.1, updated twice via Basho repo) and Riak
>>>> CS version is 2.1.0. The servers each have 64GB RAM and six 4TB disks in
>>>> raid 6 using btrfs.
>>>> 
>>>> I have been pushing random data into Riak-CS via s3cmd to see how the system
>>>> behaves. Smallest objects have been 2000 bytes, largest 100MB. I have also
>>>> been making btrfs snapshots of the entire platform data dir nightly for
>>>> backup purposes. Stop Riak CS, wait 10 seconds, stop Riak, wait 10, make
>>>> snapshot, start Riak, wait 180 seconds, start Riak CS. This is performed on
>>>> each of the servers in turn with a five minute wait in between. I have added
>>>> the waits to try spread the startup load and allow the system time to get
>>>> things running. New data is constantly pushed to the S3 API but restarting
>>>> the nodes in rotation causes by far the highest stress on the system.
>>>> 
>>>> I have encountered one problem in particular. Quite often one of the Riak
>>>> nodes starts up but after a couple of minutes it just drops, all processes
>>>> exited except for epmd.
>>>> 
>>>> Following is from /var/log/riak/console, most of the lines skipped for sake
>>>> of brevity. Normal startup stuff, as far as I can see:
>>>> 
>>>> 2015-12-16 00:26:04.446 [info] <0.7.0> Application lager started on node
>>>> 'riak at 192.168.50.32'
>>>> ...
>>>> 2015-12-16 00:26:04.490 [info] <0.72.0> alarm_handler:
>>>> {set,{system_memory_high_watermark,[]}}
>>>> ...
>>>> 2015-12-16 00:26:04.781 [info]
>>>> <0.206.0>@riak_core_capability:process_capability_changes:555 New
>>>> capability: {riak_core,vnode_routing} = proxy
>>>> ...
>>>> 2015-12-16 00:26:04.869 [info] <0.7.0> Application riak_core started on node
>>>> 'riak at 192.168.50.32'
>>>> ...
>>>> 2015-12-16 00:26:04.969 [info] <0.407.0>@riak_kv_env:doc_env:46 Environment
>>>> and OS variables:
>>>> 2015-12-16 00:26:05.124 [warning] <0.6.0> lager_error_logger_h dropped 9
>>>> messages in the last second that exceeded the limit of 100 messages/sec
>>>> 2015-12-16 00:26:05.124 [info] <0.407.0> riak_kv_env: Open file limit: 65536
>>>> 2015-12-16 00:26:05.124 [warning] <0.407.0> riak_kv_env: Cores are disabled,
>>>> this may hinder debugging
>>>> 2015-12-16 00:26:05.124 [info] <0.407.0> riak_kv_env: Erlang process limit:
>>>> 262144
>>>> 2015-12-16 00:26:05.125 [info] <0.407.0> riak_kv_env: Erlang ports limit:
>>>> 65536
>>>> 2015-12-16 00:26:05.125 [info] <0.407.0> riak_kv_env: ETS table count limit:
>>>> 256000
>>>> 2015-12-16 00:26:05.125 [info] <0.407.0> riak_kv_env: Thread pool size: 64
>>>> 2015-12-16 00:26:05.125 [info] <0.407.0> riak_kv_env: Generations before
>>>> full sweep: 0
>>>> 2015-12-16 00:26:05.125 [info] <0.407.0> riak_kv_env: Schedulers: 12 for 12
>>>> cores
>>>> 2015-12-16 00:26:05.125 [info] <0.407.0> riak_kv_env: sysctl vm.swappiness
>>>> is 0 greater than or equal to 0)
>>>> 2015-12-16 00:26:05.125 [info] <0.407.0> riak_kv_env: sysctl
>>>> net.core.wmem_default is 8388608 lesser than or equal to 8388608)
>>>> ...
>>>> 2015-12-16 00:26:05.139 [info] <0.478.0>@riak_core:wait_for_service:504
>>>> Waiting for service riak_kv to start (0 seconds)
>>>> 2015-12-16 00:26:05.158 [info]
>>>> <0.495.0>@riak_kv_entropy_manager:set_aae_throttle_limits:790 Setting AAE
>>>> throttle limits: [{-1,0},{200,10},{500,50},{750,250},{900,1000},{1100,5000}]
>>>> ...
>>>> 2015-12-16 00:26:30.160 [info]
>>>> <0.495.0>@riak_kv_entropy_manager:perhaps_log_throttle_change:853 Changing
>>>> AAE throttle from undefined -> 5000 msec/key, based on maximum vnode mailbox
>>>> size {unknown_mailbox_sizes,node_list,['riak at 192.168.50.32']} from
>>>> ['riak at 192.168.50.32']
>>>> 2015-12-16 00:27:12.053 [info] <0.478.0>@riak_core:wait_for_service:504
>>>> Waiting for service riak_kv to start (60 seconds)
>>>> 2015-12-16 00:28:25.057 [info] <0.478.0>@riak_core:wait_for_service:504
>>>> Waiting for service riak_kv to start (120 seconds)
>>>> 
>>>> And then nothing
>>>> 
>>>> From /var/log/messages:
>>>> 
>>>> Dec 16 00:26:02 storage2 su: (to riak) root on none
>>>> Dec 16 00:26:04 storage2 riak[48174]: Starting up
>>>> Dec 16 00:28:59 storage2 kernel: traps: beam.smp[48492] general protection
>>>> ip:7fcaf9402f16 sp:7fca6affcdd0 error:0 in eleveldb.so[7fcaf93b5000+93000]
>>>> Dec 16 00:28:59 storage2 run_erl[48172]: Erlang closed the connection.
>>>> 
>>>> On another node at a different time /var/log/riak/console.log had similar
>>>> messages, and also some warnings about invalid hint files, such as:
>>>> 
>>>> 2015-12-13 00:15:41.232 [warning] <0.815.0> Hintfile
>>>> '/data/riak/bitcask/570899077082383952423314387779798054553098649600/56.bitcask.hint'
>>>> invalid
>>>> 
>>>> In this latter example riak was started with "systemctl start riak" rather
>>>> than "riak start". From /var/log/messages:
>>>> 
>>>> Dec 13 00:15:29 storage1 riak: Starting riak: [  OK  ]
>>>> Dec 13 00:15:29 storage1 systemd: Started SYSV: Riak is a distributed data
>>>> store.
>>>> Dec 13 00:15:56 storage1 kernel: beam.smp[131820]: segfault at 160 ip
>>>> 00007f24c0902ce6 sp 00007f24337fddd0 error 4 in
>>>> eleveldb.so[7f24c08b5000+93000]
>>>> Dec 13 00:15:56 storage1 run_erl[131501]: Erlang closed the connection.
>>>> 
>>>> Of reported Riak bugs, this is similar to
>>>> https://github.com/basho/riak/issues/790 . However, the poster of that issue
>>>> reported that his problem was fixed by repairing leveldb partitions. I
>>>> looked at this following
>>>> http://docs.basho.com/riak/latest/ops/running/recovery/repairing-leveldb/
>>>> but didn't find any errors.
>>>> 
>>>> Incidentally, I started having problems with btrfs as well. On one node
>>>> btrfs caused a kernel crash and on another kernel killed beam.smp process
>>>> after it stopped responding for over 120 seconds while syncing to btrfs. The
>>>> kernel in Centos 7 probably isn't best suited for working with btrfs.
>>>> Advertised version is 3.10.0.
>>>> 
>>>> So, my question is what is your take on this? Is this a bug in the leveldb
>>>> library? The same one already reported? What log data would help debug or
>>>> reproduce it? Or is there potentially some problem with my setup? Or could
>>>> this be caused by a bug in btrfs? What is your take on using Riak with
>>>> btrfs?
>>>> 
>>>> --
>>>> Antti Kuusela, M.Sc
>>>> Senior Software Developer
>>>> Firstbeat Technologies Ltd.
>>>> 
>>>> 
>>>> _______________________________________________
>>>> riak-users mailing list
>>>> riak-users at lists.basho.com
>>>> http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
>>> .
>>> 
>> 
>> 
>> --
>> Antti Kuusela, M.Sc
>> Senior Software Developer
>> Firstbeat Technologies Ltd.
>> 
>> 
>> _______________________________________________
>> riak-users mailing list
>> riak-users at lists.basho.com
>> http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
> 





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