Identifying issues and resolutions¶

Is the system up?¶

If you have a report that Swift is down, perform the following basic checks:

1. Run swift functional tests.
2. From a server in your data center, use curl to check /healthcheck (see below).
3. If you have a monitoring system, check your monitoring system.
4. Check your hardware load balancers infrastructure.
5. Run swift-recon on a proxy node.

Functional tests usage¶

We would recommend that you set up the functional tests to run against your production system. Run regularly this can be a useful tool to validate that the system is configured correctly. In addition, it can provide early warning about failures in your system (if the functional tests stop working, user applications will also probably stop working).

A script for running the function tests is located in swift/.functests.

External monitoring¶

We use pingdom.com to monitor the external Swift API. We suggest the following:

• Do a GET on /healthcheck
• Create a container, make it public (x-container-read: .r*,.rlistings), create a small file in the container; do a GET on the object

Diagnose: General approach¶

• Look at service status in your monitoring system.
• In addition to system monitoring tools and issue logging by users, swift errors will often result in log entries (see Diagnose: Interpreting messages in /var/log/swift/ files).
• Look at any logs your deployment tool produces.
• Log files should be reviewed for error signatures (see below) that may point to a known issue, or root cause issues reported by the diagnostics tools, prior to escalation.

Diagnose: Swift-dispersion-report¶

The swift-dispersion-report is a useful tool to gauge the general health of the system. Configure the swift-dispersion report to cover at a minimum every disk drive in your system (usually 1% coverage). See Dispersion Report for details of how to configure and use the dispersion reporting tool.

The swift-dispersion-report tool can take a long time to run, especially if any servers are down. We suggest you run it regularly (e.g., in a cron job) and save the results. This makes it easy to refer to the last report without having to wait for a long-running command to complete.

Diagnose: Is system responding to /healthcheck?¶

When you want to establish if a swift endpoint is running, run curl -k against https://[ENDPOINT]/healthcheck.

Diagnose: Interpreting messages in /var/log/swift/ files¶

The following table lists known issues:

Diagnose: Parted reports the backup GPT table is corrupt¶

• If a GPT table is broken, a message like the following should be observed when the following command is run:

  $ sudo parted -l
  

  Error: The backup GPT table is corrupt, but the primary appears OK,
  so that will be used.
  
  OK/Cancel?
  

To fix, go to Fix broken GPT table (broken disk partition)

Diagnose: Drives diagnostic reports a FS label is not acceptable¶

If diagnostics reports something like “FS label: obj001dsk011 is not acceptable”, it indicates that a partition has a valid disk label, but an invalid filesystem label. In such cases proceed as follows:

1. Verify that the disk labels are correct:

   FS=/dev/sd#1
   
   sudo parted -l | grep object
   

2. If partition labels are inconsistent then, resolve the disk label issues before proceeding:

   sudo parted -s ${FS} name ${PART_NO} ${PART_NAME} #Partition Label
   #PART_NO is 1 for object disks and 3 for OS disks
   #PART_NAME follows the convention seen in "sudo parted -l | grep object"
   

3. If the Filesystem label is missing then create it with care:

   sudo xfs_admin -l ${FS} #Filesystem label (12 Char limit)
   
   #Check for the existence of a FS label
   
   OBJNO=<3 Length Object No.>
   
   #I.E OBJNO for sw-stbaz3-object0007 would be 007
   
   DISKNO=<3 Length Disk No.>
   
   #I.E DISKNO for /dev/sdb would be 001, /dev/sdc would be 002 etc.
   
   sudo xfs_admin -L "obj${OBJNO}dsk${DISKNO}" ${FS}
   
   #Create a FS Label
   

Diagnose: Failed LUNs¶

The swift_diagnostics mount checks may return a warning that a LUN has failed, typically accompanied by DriveAudit check failures and device errors.

Such cases are typically caused by a drive failure, and if drive check also reports a failed status for the underlying drive, then follow the procedure to replace the disk.

Otherwise the lun can be re-enabled as follows:

1. Generate a hpssacli diagnostic report. This report allows the DC team to troubleshoot potential cabling or hardware issues so it is imperative that you run it immediately when troubleshooting a failed LUN. You will come back later and grep this file for more details, but just generate it for now.

   sudo hpssacli controller all diag file=/tmp/hpacu.diag ris=on xml=off zip=off
   

Export the following variables using the below instructions before proceeding further.

1. Print a list of logical drives and their numbers and take note of the failed drive’s number and array value (example output: “array A logicaldrive 1…” would be exported as LDRIVE=1):

   sudo hpssacli controller slot=1 ld all show
   

2. Export the number of the logical drive that was retrieved from the previous command into the LDRIVE variable:

   export LDRIVE=<LogicalDriveNumber>
   

3. Print the array value and Port:Box:Bay for all drives and take note of the Port:Box:Bay for the failed drive (example output: ” array A physicaldrive 2C:1:1…” would be exported as PBOX=2C:1:1). Match the array value of this output with the array value obtained from the previous command to be sure you are working on the same drive. Also, the array value usually matches the device name (For example, /dev/sdc in the case of “array c”), but we will run a different command to be sure we are operating on the correct device.

   sudo hpssacli controller slot=1 pd all show
   

1. Export the Port:Box:Bay for the failed drive into the PBOX variable:

   export PBOX=<Port:Box:Bay>
   

2. Print the physical device information and take note of the Disk Name (example output: “Disk Name: /dev/sdk” would be exported as DEV=/dev/sdk):

   sudo hpssacli controller slot=1 ld ${LDRIVE} show detail | grep -i "Disk Name"
   

3. Export the device name variable from the preceding command (example: /dev/sdk):

   export DEV=<Device>
   

4. Export the filesystem variable. Disks that are split between the operating system and data storage, typically sda and sdb, should only have repairs done on their data filesystem, usually /dev/sda2 and /dev/sdb2, Other data only disks have just one partition on the device, so the filesystem will be 1. In any case you should verify the data filesystem by running df -h | grep /srv/node and using the listed data filesystem for the device in question as the export. For example: /dev/sdk1.

   export FS=<Filesystem>
   

5. Verify the LUN is failed, and the device is not:

   sudo hpssacli controller slot=1 ld all show
   sudo hpssacli controller slot=1 pd all show
   sudo hpssacli controller slot=1 ld ${LDRIVE} show detail
   sudo hpssacli controller slot=1 pd ${PBOX} show detail
   

6. Stop the swift and rsync service:

   sudo service rsync stop
   sudo swift-init shutdown all
   

7. Unmount the problem drive, fix the LUN and the filesystem:

   sudo umount ${FS}
   

8. If umount fails, you should run lsof search for the mountpoint and kill any lingering processes before repeating the unpount:

   sudo hpacucli controller slot=1 ld ${LDRIVE} modify reenable
   sudo xfs_repair ${FS}
   

9. If the xfs_repair complains about possible journal data, use the xfs_repair -L option to zeroise the journal log.

10. Once complete test-mount the filesystem, and tidy up its lost and found area.

    sudo mount ${FS} /mnt
    sudo rm -rf /mnt/lost+found/
    sudo umount /mnt
    

11. Mount the filesystem and restart swift and rsync.

12. Run the following to determine if a DC ticket is needed to check the cables on the node:

    grep -y media.exchanged /tmp/hpacu.diag
    grep -y hot.plug.count /tmp/hpacu.diag
    

13. If the output reports any non 0x00 values, it suggests that the cables should be checked. For example, log a DC ticket to check the sas cables between the drive and the expander.

Diagnose: Slow disk devices¶

If the diagnostics report a message such as sda: drive is slow, you should log onto the node and run the following command (remove -c 1 option to continuously monitor the data):

$ /usr/bin/collectl -s D -c 1
waiting for 1 second sample...
# DISK STATISTICS (/sec)
#          <---------reads---------><---------writes---------><--------averages--------> Pct
#Name       KBytes Merged  IOs Size  KBytes Merged  IOs Size  RWSize  QLen  Wait SvcTim Util
sdb            204      0   33    6      43      0    4   11       6     1     7      6   23
sda             84      0   13    6     108     21    6   18      10     1     7      7   13
sdc            100      0   16    6       0      0    0    0       6     1     7      6    9
sdd            140      0   22    6      22      0    2   11       6     1     9      9   22
sde             76      0   12    6     255      0   52    5       5     1     2      1   10
sdf            276      0   44    6       0      0    0    0       6     1    11      8   38
sdg            112      0   17    7      18      0    2    9       6     1     7      7   13
sdh           3552      0   73   49       0      0    0    0      48     1     9      8   62
sdi             72      0   12    6       0      0    0    0       6     1     8      8   10
sdj            112      0   17    7      22      0    2   11       7     1    10      9   18
sdk            120      0   19    6      21      0    2   11       6     1     8      8   16
sdl            144      0   22    7      18      0    2    9       6     1     9      7   18
dm-0             0      0    0    0       0      0    0    0       0     0     0      0    0
dm-1             0      0    0    0      60      0   15    4       4     0     0      0    0
dm-2             0      0    0    0      48      0   12    4       4     0     0      0    0
dm-3             0      0    0    0       0      0    0    0       0     0     0      0    0
dm-4             0      0    0    0       0      0    0    0       0     0     0      0    0
dm-5             0      0    0    0       0      0    0    0       0     0     0      0    0

Look at the Wait and SvcTime values. It is not normal for these values to exceed 50msec. This is known to impact customer performance (upload/download). For a controller problem, many/all drives will show long wait and service times. A reboot may correct the problem; otherwise hardware replacement is needed.

Another way to look at the data is as follows:

$ /opt/hp/syseng/disk-anal.pl -d
Disk: sda  Wait: 54580 371  65  25  12   6   6   0   1   2   0  46
Disk: sdb  Wait: 54532 374  96  36  16   7   4   1   0   2   0  46
Disk: sdc  Wait: 54345 554 105  29  15   4   7   1   4   4   0  46
Disk: sdd  Wait: 54175 553 254  31  20  11   6   6   2   2   1  53
Disk: sde  Wait: 54923  66  56  15   8   7   7   0   1   0   2  29
Disk: sdf  Wait: 50952 941 565 403 426 366 442 447 338  99  38  97
Disk: sdg  Wait: 50711 689 808 562 642 675 696 185  43  14   7  82
Disk: sdh  Wait: 51018 668 688 483 575 542 692 275  55  22   9  87
Disk: sdi  Wait: 51012 1011 849 672 568 240 344 280  38  13   6  81
Disk: sdj  Wait: 50724 743 770 586 662 509 684 283  46  17  11  79
Disk: sdk  Wait: 50886 700 585 517 633 511 729 352  89  23   8  81
Disk: sdl  Wait: 50106 617 794 553 604 504 532 501 288 234 165 216
Disk: sda  Time: 55040  22  16   6   1   1  13   0   0   0   3  12

Disk: sdb  Time: 55014  41  19   8   3   1   8   0   0   0   3  17
Disk: sdc  Time: 55032  23  14   8   9   2   6   1   0   0   0  19
Disk: sdd  Time: 55022  29  17  12   6   2  11   0   0   0   1  14
Disk: sde  Time: 55018  34  15  11  12   1   9   0   0   0   2  12
Disk: sdf  Time: 54809 250  45   7   1   0   0   0   0   0   1   1
Disk: sdg  Time: 55070  36   6   2   0   0   0   0   0   0   0   0
Disk: sdh  Time: 55079  33   2   0   0   0   0   0   0   0   0   0
Disk: sdi  Time: 55074  28   7   2   0   0   2   0   0   0   0   1
Disk: sdj  Time: 55067  35  10   0   1   0   0   0   0   0   0   1
Disk: sdk  Time: 55068  31  10   3   0   0   1   0   0   0   0   1
Disk: sdl  Time: 54905 130  61   7   3   4   1   0   0   0   0   3

This shows the historical distribution of the wait and service times over a day. This is how you read it:

• sda did 54580 operations with a short wait time, 371 operations with a longer wait time and 65 with an even longer wait time.
• sdl did 50106 operations with a short wait time, but as you can see many took longer.

There is a clear pattern that sdf to sdl have a problem. Actually, sda to sde would more normally have lots of zeros in their data. But maybe this is a busy system. In this example it is worth changing the controller as the individual drives may be ok.

After the controller is changed, use collectl -s D as described above to see if the problem has cleared. disk-anal.pl will continue to show historical data. You can look at recent data as follows. It only looks at data from 13:15 to 14:15. As you can see, this is a relatively clean system (few if any long wait or service times):

$ /opt/hp/syseng/disk-anal.pl -d -t 13:15-14:15
Disk: sda  Wait:  3600   0   0   0   0   0   0   0   0   0   0   0
Disk: sdb  Wait:  3600   0   0   0   0   0   0   0   0   0   0   0
Disk: sdc  Wait:  3600   0   0   0   0   0   0   0   0   0   0   0
Disk: sdd  Wait:  3600   0   0   0   0   0   0   0   0   0   0   0
Disk: sde  Wait:  3600   0   0   0   0   0   0   0   0   0   0   0
Disk: sdf  Wait:  3600   0   0   0   0   0   0   0   0   0   0   0
Disk: sdg  Wait:  3594   6   0   0   0   0   0   0   0   0   0   0
Disk: sdh  Wait:  3600   0   0   0   0   0   0   0   0   0   0   0
Disk: sdi  Wait:  3600   0   0   0   0   0   0   0   0   0   0   0
Disk: sdj  Wait:  3600   0   0   0   0   0   0   0   0   0   0   0
Disk: sdk  Wait:  3600   0   0   0   0   0   0   0   0   0   0   0
Disk: sdl  Wait:  3599   1   0   0   0   0   0   0   0   0   0   0
Disk: sda  Time:  3600   0   0   0   0   0   0   0   0   0   0   0
Disk: sdb  Time:  3600   0   0   0   0   0   0   0   0   0   0   0
Disk: sdc  Time:  3600   0   0   0   0   0   0   0   0   0   0   0
Disk: sdd  Time:  3600   0   0   0   0   0   0   0   0   0   0   0
Disk: sde  Time:  3600   0   0   0   0   0   0   0   0   0   0   0
Disk: sdf  Time:  3600   0   0   0   0   0   0   0   0   0   0   0
Disk: sdg  Time:  3594   6   0   0   0   0   0   0   0   0   0   0
Disk: sdh  Time:  3600   0   0   0   0   0   0   0   0   0   0   0
Disk: sdi  Time:  3600   0   0   0   0   0   0   0   0   0   0   0
Disk: sdj  Time:  3600   0   0   0   0   0   0   0   0   0   0   0
Disk: sdk  Time:  3600   0   0   0   0   0   0   0   0   0   0   0
Disk: sdl  Time:  3599   1   0   0   0   0   0   0   0   0   0   0

For long wait times, where the service time appears normal is to check the logical drive cache status. While the cache may be enabled, it can be disabled on a per-drive basis.

Diagnose: Slow network link - Measuring network performance¶

Network faults can cause performance between Swift nodes to degrade. Testing with netperf is recommended. Other methods (such as copying large files) may also work, but can produce inconclusive results.

Install netperf on all systems if not already installed. Check that the UFW rules for its control port are in place. However, there are no pre-opened ports for netperf’s data connection. Pick a port number. In this example, 12866 is used because it is one higher than netperf’s default control port number, 12865. If you get very strange results including zero values, you may not have gotten the data port opened in UFW at the target or may have gotten the netperf command-line wrong.

Pick a source and target node. The source is often a proxy node and the target is often an object node. Using the same source proxy you can test communication to different object nodes in different AZs to identity possible bottlenecks.

Diagnose: Remapping sectors experiencing UREs¶

1. Find the bad sector, device, and filesystem in kern.log.

2. Set the environment variables SEC, DEV & FS, for example:

   SEC=2930954256
   DEV=/dev/sdi
   FS=/dev/sdi1
   

3. Verify that the sector is bad:

   sudo dd if=${DEV} of=/dev/null bs=512 count=1 skip=${SEC}
   

4. If the sector is bad this command will output an input/output error:

   dd: reading `/dev/sdi`: Input/output error
   0+0 records in
   0+0 records out
   

5. Prevent chef from attempting to re-mount the filesystem while the repair is in progress:

   sudo mv /etc/chef/client.pem /etc/chef/xx-client.xx-pem
   

6. Stop the swift and rsync service:

   sudo service rsync stop
   sudo swift-init shutdown all
   

7. Unmount the problem drive:

   sudo umount ${FS}
   

8. Overwrite/remap the bad sector:

   sudo dd_rescue -d -A -m8b -s ${SEC}b ${DEV} ${DEV}
   

9. This command should report an input/output error the first time it is run. Run the command a second time, if it successfully remapped the bad sector it should not report an input/output error.

10. Verify the sector is now readable:

    sudo dd if=${DEV} of=/dev/null bs=512 count=1 skip=${SEC}
    

11. If the sector is now readable this command should not report an input/output error.

12. If more than one problem sector is listed, set the SEC environment variable to the next sector in the list:

    SEC=123456789
    

13. Repeat from step 8.

14. Repair the filesystem:

    sudo xfs_repair ${FS}
    

15. If xfs_repair reports that the filesystem has valuable filesystem changes:

    sudo xfs_repair ${FS}
    Phase 1 - find and verify superblock...
    Phase 2 - using internal log
            - zero log...
    ERROR: The filesystem has valuable metadata changes in a log which
    needs to be replayed.
    Mount the filesystem to replay the log, and unmount it before
    re-running xfs_repair.
    If you are unable to mount the filesystem, then use the -L option to
    destroy the log and attempt a repair. Note that destroying the log may
    cause corruption -- please attempt a mount of the filesystem before
    doing this.
    

16. You should attempt to mount the filesystem, and clear the lost+found area:

    sudo mount $FS /mnt
    sudo rm -rf /mnt/lost+found/*
    sudo umount /mnt
    

17. If the filesystem fails to mount then you will need to use the xfs_repair -L option to force log zeroing. Repeat step 11.

18. If xfs_repair reports that an additional input/output error has been encountered, get the sector details as follows:

    sudo grep "I/O error" /var/log/kern.log | grep sector | tail -1
    

19. If new input/output error is reported then set the SEC environment variable to the problem sector number:

    SEC=234567890
    

20. Repeat from step 8

21. Remount the filesystem and restart swift and rsync.

    • If all UREs in the kern.log have been fixed and you are still unable to have xfs_repair disk, it is possible that the URE’s have corrupted the filesystem or possibly destroyed the drive altogether. In this case, the first step is to re-format the filesystem and if this fails, get the disk replaced.

Diagnose: High system latency¶

• A bad NIC on a proxy server. However, as explained above, this usually causes the peak to rise, but average should remain near normal parameters. A quick fix is to shutdown the proxy.
• A stuck memcache server. Accepts connections, but then will not respond. Expect to see timeout messages in /var/log/proxy.log (port 11211). Swift Diags will also report this as a failed node/port. A quick fix is to shutdown the proxy server.
• A bad/broken object server can also cause problems if the accounts used by the monitor program happen to live on the bad object server.
• A general network problem within the data canter. Compare the results with the Pingdom monitors to see if they also have a problem.

Diagnose: Interface reports errors¶

Should a network interface on a Swift node begin reporting network errors, it may well indicate a cable, switch, or network issue.

Get an overview of the interface with:

sudo ifconfig eth{n}
sudo ethtool eth{n}

The Link Detected: indicator will read yes if the nic is cabled.

Establish the adapter type with:

sudo ethtool  -i eth{n}

Gather the interface statistics with:

sudo ethtool  -S eth{n}

If the nick supports self test, this can be performed with:

sudo ethtool  -t eth{n}

Self tests should read PASS if the nic is operating correctly.

Nic module drivers can be re-initialised by carefully removing and re-installing the modules (this avoids rebooting the server). For example, mellanox drivers use a two part driver mlx4_en and mlx4_core. To reload these you must carefully remove the mlx4_en (ethernet) then the mlx4_core modules, and reinstall them in the reverse order.

As the interface will be disabled while the modules are unloaded, you must be very careful not to lock yourself out so it may be better to script this.

Diagnose: Hung swift object replicator¶

A replicator reports in its log that remaining time exceeds 100 hours. This may indicate that the swift object-replicator is stuck and not making progress. Another useful way to check this is with the ‘swift-recon -r’ command on a swift proxy server:

sudo swift-recon -r
===============================================================================

--> Starting reconnaissance on 384 hosts
===============================================================================
[2013-07-17 12:56:19] Checking on replication
[replication_time] low: 2, high: 80, avg: 28.8, total: 11037, Failed: 0.0%, no_result: 0, reported: 383
Oldest completion was 2013-06-12 22:46:50 (12 days ago) by 192.168.245.3:6200.
Most recent completion was 2013-07-17 12:56:19 (5 seconds ago) by 192.168.245.5:6200.
===============================================================================

The Oldest completion line in this example indicates that the object-replicator on swift object server 192.168.245.3 has not completed the replication cycle in 12 days. This replicator is stuck. The object replicator cycle is generally less than 1 hour. Though an replicator cycle of 15-20 hours can occur if nodes are added to the system and a new ring has been deployed.

You can further check if the object replicator is stuck by logging on the object server and checking the object replicator progress with the following command:

#  sudo grep object-rep /var/log/swift/background.log | grep -e "Starting object replication" -e "Object replication complete" -e "partitions rep"
Jul 16 06:25:46 192.168.245.4 object-replicator 15344/16450 (93.28%) partitions replicated in 69018.48s (0.22/sec, 22h remaining)
Jul 16 06:30:46 192.168.245.4object-replicator 15344/16450 (93.28%) partitions replicated in 69318.58s (0.22/sec, 22h remaining)
Jul 16 06:35:46 192.168.245.4 object-replicator 15344/16450 (93.28%) partitions replicated in 69618.63s (0.22/sec, 23h remaining)
Jul 16 06:40:46 192.168.245.4 object-replicator 15344/16450 (93.28%) partitions replicated in 69918.73s (0.22/sec, 23h remaining)
Jul 16 06:45:46 192.168.245.4 object-replicator 15348/16450 (93.30%) partitions replicated in 70218.75s (0.22/sec, 24h remaining)
Jul 16 06:50:47 192.168.245.4object-replicator 15348/16450 (93.30%) partitions replicated in 70518.85s (0.22/sec, 24h remaining)
Jul 16 06:55:47 192.168.245.4 object-replicator 15348/16450 (93.30%) partitions replicated in 70818.95s (0.22/sec, 25h remaining)
Jul 16 07:00:47 192.168.245.4 object-replicator 15348/16450 (93.30%) partitions replicated in 71119.05s (0.22/sec, 25h remaining)
Jul 16 07:05:47 192.168.245.4 object-replicator 15348/16450 (93.30%) partitions replicated in 71419.15s (0.21/sec, 26h remaining)
Jul 16 07:10:47 192.168.245.4object-replicator 15348/16450 (93.30%) partitions replicated in 71719.25s (0.21/sec, 26h remaining)
Jul 16 07:15:47 192.168.245.4 object-replicator 15348/16450 (93.30%) partitions replicated in 72019.27s (0.21/sec, 27h remaining)
Jul 16 07:20:47 192.168.245.4object-replicator 15348/16450 (93.30%) partitions replicated in 72319.37s (0.21/sec, 27h remaining)
Jul 16 07:25:47 192.168.245.4 object-replicator 15348/16450 (93.30%) partitions replicated in 72619.47s (0.21/sec, 28h remaining)
Jul 16 07:30:47 192.168.245.4 object-replicator 15348/16450 (93.30%) partitions replicated in 72919.56s (0.21/sec, 28h remaining)
Jul 16 07:35:47 192.168.245.4 object-replicator 15348/16450 (93.30%) partitions replicated in 73219.67s (0.21/sec, 29h remaining)
Jul 16 07:40:47 192.168.245.4 object-replicator 15348/16450 (93.30%) partitions replicated in 73519.76s (0.21/sec, 29h remaining)

The above status is output every 5 minutes to /var/log/swift/background.log.

One of the reasons for the object replicator hanging like this is filesystem corruption on the drive. The following is a typical log entry of a corrupted filesystem detected by the object replicator:

# sudo bzgrep "Remote I/O error" /var/log/swift/background.log* |grep srv | - tail -1
Jul 12 03:33:30 192.168.245.4 object-replicator STDOUT: ERROR:root:Error hashing suffix#012Traceback (most recent call last):#012 File
"/usr/lib/python2.7/dist-packages/swift/obj/replicator.py", line 199, in get_hashes#012 hashes[suffix] = hash_suffix(suffix_dir,
reclaim_age)#012 File "/usr/lib/python2.7/dist-packages/swift/obj/replicator.py", line 84, in hash_suffix#012 path_contents =
sorted(os.listdir(path))#012OSError: [Errno 121] Remote I/O error: '/srv/node/disk4/objects/1643763/b51'

An ls of the problem file or directory usually shows something like the following:

# ls -l /srv/node/disk4/objects/1643763/b51
ls: cannot access /srv/node/disk4/objects/1643763/b51: Remote I/O error

If no entry with Remote I/O error occurs in the background.log it is not possible to determine why the object-replicator is hung. It may be that the Remote I/O error entry is older than 7 days and so has been rotated out of the logs. In this scenario it may be best to simply restart the object-replicator.

1. Stop the object-replicator:

   # sudo swift-init object-replicator stop
   

2. Make sure the object replicator has stopped, if it has hung, the stop command will not stop the hung process:

   # ps auxww | - grep swift-object-replicator
   

3. If the previous ps shows the object-replicator is still running, kill the process:

   # kill -9 <pid-of-swift-object-replicator>
   

4. Start the object-replicator:

   # sudo swift-init object-replicator start
   

If the above grep did find an Remote I/O error then it may be possible to repair the problem filesystem.

1. Stop swift and rsync:

   # sudo swift-init all shutdown
   # sudo service rsync stop
   

2. Make sure all swift process have stopped:

   # ps auxww | grep swift | grep python
   

3. Kill any swift processes still running.

4. Unmount the problem filesystem:

   # sudo umount /srv/node/disk4
   

5. Repair the filesystem:

   # sudo xfs_repair -P /dev/sde1
   

6. If the xfs_repair fails then it may be necessary to re-format the filesystem. See Procedure: Fix broken XFS filesystem. If the xfs_repair is successful, re-enable chef using the following command and replication should commence again.

Diagnose: High CPU load¶

The CPU load average on an object server, as shown with the ‘uptime’ command, is typically under 10 when the server is lightly-moderately loaded:

$ uptime
07:59:26 up 99 days,  5:57,  1 user,  load average: 8.59, 8.39, 8.32

During times of increased activity, due to user transactions or object replication, the CPU load average can increase to to around 30.

However, sometimes the CPU load average can increase significantly. The following is an example of an object server that has extremely high CPU load:

$ uptime
07:44:02 up 18:22,  1 user,  load average: 407.12, 406.36, 404.59

Further issues and resolutions¶

sudo swift-init all start

% sudo swift-init all reload

sudo ethtool -s eth0 speed 1000

sudo lshw -class

sudo swift-init <service> reload

sudo swift-init object-replicator reload