IBM DS flash copy¶
IBM Flash copy allow multi-target block device replication. After create initial flash copy, the relation can persist. These features allow opensvc to drive services using a flash copy device set. Such services are often used for maintenance, pre-production and performance testing environments, where the source device set is used for production. The following documentation presents the configuration of such a service.
A service with only flash copy sync resources can be defined to drive the clone of other servers, just for the benefit of centralized logging and scheduling.
- Resyncflash (or rmflash/mkflash) action to pair source/target. This command verifies the service is down before proceeding.
- syncresync --force
- Bypass the sync_min_delay protection.
- The last resync occured less than 'sync_max_delay' minutes ago.
- The last replication occured more than ‘sync_max_delay’ minutes ago.
- Device are in a unexpected state or not present in the flash copy persistent pair list.
The dscli commands must be installed in the standard location on the nodes running this service resource type.
<OSVCETC>/auth.conf must exist and contain credentials to access the manager for each array. The agent enforce this file permissions is 600 and is owned by root.
[IBM.XXXX-XXXXXXX] type = ibmds hmc1 = 10.10.10.10 hmc2 = username = opensvc
Use dscli commands to create pwfile in <OSVCVAR>. The pwfile's name must be the same as the array. For exemple
dscli managepwfile -action add -mc1 22.214.171.124 -mc2 126.96.36.199 -pwfile /var/lib/opensvc/IBM.2107-00AAA00.pwfile -name opensvc -pw xxx
Service configuration file¶
# # IBM flash copy # ;[sync#1] ;type = ibmdssnap ;sync_max_delay = 10512000 # # 'array' # mandatory. The name of the IBM storage array, as seen by the manager. # Also used in etc/auth.conf # ;array = IBM.XXXX-XXXXXXX # # ‘pairs’ # mandatory. whitespace-separated list of device pairs (source/target) to drive with this ressource. # ;pairs = 0001:0002 0101:0102 0003:0004 # # ‘bgcopy’ # optional. Default True. # After background copy, all track are available to the target. # If False, array wait write on source track to copy delta on the target. In this case, read a no copied track on the target is read on the source. ;bgcopy = true # # ‘recording’ # optional. Default True. The recording target allow resyncs delta-based and restore delta only. One recording target is possible. # ;recording = true # flash copy with recording and bgcopy options looks like delta-based clone feature # flash copy without recording and bgcopy options looks like snapshot feature # flash copy without recording option but with bgcopy option looks like full copy feature
You can setup as many sync resources as needed to ensure a consistent replication scenario.
IBM DS flash copy configuration¶
You have to create the persistent flash copy manually once. This requires two existing devices.
Resync a started service snapshots¶
# svcmgr -s iiststibmds stop && \ svcmgr -s iiststibmds syncresync && \ svcmgr -s iiststibmds start
Resync a stopped service snapshots¶
# svcmgr -s iiststibmds syncresync 2014-09-18 23:04:02,189 - IISTSTIBMDS.SYNC#1 - INFO - resyncflash - dev IBM.XXXX-XXXXXXX -persist -record -cp 0001:0002 0101:0102 0003:0004 | /opt/ibm/dscli/dscli -hmc1 10.10.10.10 -user opensvc -pwfile /var/lib/opensvc/IBM.XXXX-XXXXXXX.pwfile 2014-09-18 23:04:05,621 - IISTSTIBMDS.SYNC#1 - INFO - Date/Time: September 18, 2014 11:04:04 PM CEST IBM DSCLI Version: 188.8.131.527 DS: IBM.XXXX-XXXXXXX Date/Time: September 18, 2014 11:04:04 PM CEST IBM DSCLI Version: 184.108.40.2067 DS: IBM.XXXX-XXXXXXX CMUC00168I resyncflash: FlashCopy volume pair 0001:0002 successfully resynchronized. CMUC00168I resyncflash: FlashCopy volume pair 0101:0102 successfully resynchronized. CMUC00168I resyncflash: FlashCopy volume pair 0003:0004 successfully resynchronized.