Software configuration procedures¶

Fix broken GPT table (broken disk partition)¶

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

  $ sudo parted -l
  

• … is run.

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

1. To fix this, firstly install the gdisk program to fix this:

   $ sudo aptitude install gdisk
   

2. Run gdisk for the particular drive with the damaged partition:

3. On the command prompt, type r (recovery and transformation options), followed by d (use main GPT header) , v (verify disk) and finally w (write table to disk and exit). Will also need to enter Y when prompted in order to confirm actions.

   Command (? for help): r
   
   Recovery/transformation command (? for help): d
   
   Recovery/transformation command (? for help): v
   
   Caution: The CRC for the backup partition table is invalid. This table may
   be corrupt. This program will automatically create a new backup partition
   table when you save your partitions.
   
   Caution: Partition 1 doesn't begin on a 8-sector boundary. This may
   result in degraded performance on some modern (2009 and later) hard disks.
   
   Caution: Partition 2 doesn't begin on a 8-sector boundary. This may
   result in degraded performance on some modern (2009 and later) hard disks.
   
   Caution: Partition 3 doesn't begin on a 8-sector boundary. This may
   result in degraded performance on some modern (2009 and later) hard disks.
   
   Identified 1 problems!
   
   Recovery/transformation command (? for help): w
   
   Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING
   PARTITIONS!!
   
   Do you want to proceed, possibly destroying your data? (Y/N): Y
   
   OK; writing new GUID partition table (GPT).
   The operation has completed successfully.
   

4. Running the command:

   $ sudo parted /dev/sd#
   

5. Should now show that the partition is recovered and healthy again.

6. Finally, uninstall gdisk from the node:

   $ sudo aptitude remove gdisk
   

Procedure: Fix broken XFS filesystem¶

1. A filesystem may be corrupt or broken if the following output is observed when checking its label:

   $ sudo xfs_admin -l /dev/sd#
     cache_node_purge: refcount was 1, not zero (node=0x25d5ee0)
     xfs_admin: cannot read root inode (117)
     cache_node_purge: refcount was 1, not zero (node=0x25d92b0)
     xfs_admin: cannot read realtime bitmap inode (117)
     bad sb magic # 0 in AG 1
     failed to read label in AG 1
   

2. Run the following commands to remove the broken/corrupt filesystem and replace. (This example uses the filesystem /dev/sdb2) Firstly need to replace the partition:

   $ sudo parted
   GNU Parted 2.3
   Using /dev/sda
   Welcome to GNU Parted! Type 'help' to view a list of commands.
   (parted) select /dev/sdb
   Using /dev/sdb
   (parted) p
   Model: HP LOGICAL VOLUME (scsi)
   Disk /dev/sdb: 2000GB
   Sector size (logical/physical): 512B/512B
   Partition Table: gpt
   
   Number  Start   End     Size    File system  Name   Flags
   1      17.4kB  1024MB  1024MB  ext3                 boot
   2      1024MB  1751GB  1750GB  xfs          sw-aw2az1-object045-disk1
   3      1751GB  2000GB  249GB                        lvm
   
   (parted) rm 2
   (parted) mkpart primary 2 -1
   Warning: You requested a partition from 2000kB to 2000GB.
   The closest location we can manage is 1024MB to 1751GB.
   Is this still acceptable to you?
   Yes/No? Yes
   Warning: The resulting partition is not properly aligned for best performance.
   Ignore/Cancel? Ignore
   (parted) p
   Model: HP LOGICAL VOLUME (scsi)
   Disk /dev/sdb: 2000GB
   Sector size (logical/physical): 512B/512B
   Partition Table: gpt
   
   Number  Start   End     Size    File system  Name     Flags
   1      17.4kB  1024MB  1024MB  ext3                  boot
   2      1024MB  1751GB  1750GB  xfs          primary
   3      1751GB  2000GB  249GB                         lvm
   
   (parted) quit
   

3. Next step is to scrub the filesystem and format:

     $ sudo dd if=/dev/zero of=/dev/sdb2 bs=$((1024*1024)) count=1
     1+0 records in
     1+0 records out
     1048576 bytes (1.0 MB) copied, 0.00480617 s, 218 MB/s
     $ sudo /sbin/mkfs.xfs -f -i size=1024 /dev/sdb2
     meta-data=/dev/sdb2              isize=1024   agcount=4, agsize=106811524 blks
            =                       sectsz=512   attr=2, projid32bit=0
   data     =                       bsize=4096   blocks=427246093, imaxpct=5
            =                       sunit=0      swidth=0 blks
   naming   =version 2              bsize=4096   ascii-ci=0
   log      =internal log           bsize=4096   blocks=208616, version=2
            =                       sectsz=512   sunit=0 blks, lazy-count=1
   realtime =none                   extsz=4096   blocks=0, rtextents=0
   

4. You should now label and mount your filesystem.

5. Can now check to see if the filesystem is mounted using the command:

   $ mount
   

Procedure: Checking if an account is okay¶

You must know the tenant/project ID. You can check if the account is okay as follows from a proxy.

$ sudo -u swift  /opt/hp/swift/bin/swift-direct show AUTH_<project-id>

The response will either be similar to a swift list of the account containers, or an error indicating that the resource could not be found.

Alternatively, you can use swift-get-nodes to find the account database files. Run the following on a proxy:

$ sudo swift-get-nodes /etc/swift/account.ring.gz  AUTH_<project-id>

The response will print curl/ssh commands that will list the replicated account databases. Use the indicated curl or ssh commands to check the status and existence of the account.

Procedure: Getting swift account stats¶

This procedure describes how you determine the swift usage for a given swift account, that is the number of containers, number of objects and total bytes used. To do this you will need the project ID.

Log onto one of the swift proxy servers.

Use swift-direct to show this accounts usage:

$ sudo -u swift /opt/hp/swift/bin/swift-direct show AUTH_<project-id>
Status: 200
      Content-Length: 0
      Accept-Ranges: bytes
      X-Timestamp: 1379698586.88364
      X-Account-Bytes-Used: 67440225625994
      X-Account-Container-Count: 1
      Content-Type: text/plain; charset=utf-8
      X-Account-Object-Count: 8436776
      Status: 200
      name: my_container  count: 8436776  bytes: 67440225625994

This account has 1 container. That container has 8436776 objects. The total bytes used is 67440225625994.

Procedure: Revive a deleted account¶

Swift accounts are normally not recreated. If a tenant/project is deleted, the account can then be deleted. If the user wishes to use Swift again, the normal process is to create a new tenant/project – and hence a new Swift account.

However, if the Swift account is deleted, but the tenant/project is not deleted from Keystone, the user can no longer access the account. This is because the account is marked deleted in Swift. You can revive the account as described in this process.

The solution is to delete the account database files and re-create the account as follows:

1. You must know the tenant/project ID. The account name is AUTH_<project-id>. In this example, the tenant/project is 4ebe3039674d4864a11fe0864ae4d905 so the Swift account name is AUTH_4ebe3039674d4864a11fe0864ae4d905.

2. Use swift-get-nodes to locate the account’s database files (on three servers). The output has been truncated so we can focus on the import pieces of data:

   $ sudo swift-get-nodes /etc/swift/account.ring.gz AUTH_4ebe3039674d4864a11fe0864ae4d905
   ...
   curl -I -XHEAD "http://192.168.245.5:6202/disk1/3934/AUTH_4ebe3039674d4864a11fe0864ae4d905"
   curl -I -XHEAD "http://192.168.245.3:6202/disk0/3934/AUTH_4ebe3039674d4864a11fe0864ae4d905"
   curl -I -XHEAD "http://192.168.245.4:6202/disk1/3934/AUTH_4ebe3039674d4864a11fe0864ae4d905"
   ...
   Use your own device location of servers:
   such as "export DEVICE=/srv/node"
   ssh 192.168.245.5 "ls -lah ${DEVICE:-/srv/node*}/disk1/accounts/3934/052/f5ecf8b40de3e1b0adb0dbe576874052"
   ssh 192.168.245.3 "ls -lah ${DEVICE:-/srv/node*}/disk0/accounts/3934/052/f5ecf8b40de3e1b0adb0dbe576874052"
   ssh 192.168.245.4 "ls -lah ${DEVICE:-/srv/node*}/disk1/accounts/3934/052/f5ecf8b40de3e1b0adb0dbe576874052"
   ...
   note: `/srv/node*` is used as default value of `devices`, the real value is set in the config file on each storage node.
   

3. Before proceeding check that the account is really deleted by using curl. Execute the commands printed by swift-get-nodes. For example:

   $ curl -I -XHEAD "http://192.168.245.5:6202/disk1/3934/AUTH_4ebe3039674d4864a11fe0864ae4d905"
   HTTP/1.1 404 Not Found
   Content-Length: 0
   Content-Type: text/html; charset=utf-8
   

   Repeat for the other two servers (192.168.245.3 and 192.168.245.4). A 404 Not Found indicates that the account is deleted (or never existed).

   If you get a 204 No Content response, do not proceed.

4. Use the ssh commands printed by swift-get-nodes to check if database files exist. For example:

   $  ssh 192.168.245.5 "ls -lah ${DEVICE:-/srv/node*}/disk1/accounts/3934/052/f5ecf8b40de3e1b0adb0dbe576874052"
   total 20K
   drwxr-xr-x 2 swift swift 110 Mar  9 10:22 .
   drwxr-xr-x 3 swift swift  45 Mar  9 10:18 ..
   -rw------- 1 swift swift 17K Mar  9 10:22 f5ecf8b40de3e1b0adb0dbe576874052.db
   -rw-r--r-- 1 swift swift   0 Mar  9 10:22 f5ecf8b40de3e1b0adb0dbe576874052.db.pending
   -rwxr-xr-x 1 swift swift   0 Mar  9 10:18 .lock
   

   Repeat for the other two servers (192.168.245.3 and 192.168.245.4).

   If no files exist, no further action is needed.

5. Stop Swift processes on all nodes listed by swift-get-nodes (In this example, that is 192.168.245.3, 192.168.245.4 and 192.168.245.5).

6. We recommend you make backup copies of the database files.

7. Delete the database files. For example:

   $ ssh 192.168.245.5
   $ cd /srv/node/disk1/accounts/3934/052/f5ecf8b40de3e1b0adb0dbe576874052
   $ sudo rm *
   

   Repeat for the other two servers (192.168.245.3 and 192.168.245.4).

8. Restart Swift on all three servers

At this stage, the account is fully deleted. If you enable the auto-create option, the next time the user attempts to access the account, the account will be created. You may also use swiftly to recreate the account.

Procedure: Temporarily stop load balancers from directing traffic to a proxy server¶

You can stop the load balancers sending requests to a proxy server as follows. This can be useful when a proxy is misbehaving but you need Swift running to help diagnose the problem. By removing from the load balancers, customer’s are not impacted by the misbehaving proxy.

1. Ensure that in /etc/swift/proxy-server.conf the disable_path variable is set to /etc/swift/disabled-by-file.

2. Log onto the proxy node.

3. Shut down Swift as follows:

   sudo swift-init proxy shutdown
   

   Note

   Shutdown, not stop.

4. Create the /etc/swift/disabled-by-file file. For example:

   sudo touch /etc/swift/disabled-by-file
   

5. Optional, restart Swift:

   sudo swift-init proxy start
   

It works because the healthcheck middleware looks for /etc/swift/disabled-by-file. If it exists, the middleware will return 503/error instead of 200/OK. This means the load balancer should stop sending traffic to the proxy.

Procedure: Ad-Hoc disk performance test¶

You can get an idea whether a disk drive is performing as follows:

sudo dd bs=1M count=256 if=/dev/zero conv=fdatasync of=/srv/node/disk11/remember-to-delete-this-later

You can expect ~600MB/sec. If you get a low number, repeat many times as Swift itself may also read or write to the disk, hence giving a lower number.