Arda Oral

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Use Case DB Backup Workflow with DB Snapshot
Postprocessing

• Arda Oral
• Professional Services Engineer

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Goal

• Hava a fallback database available which can be
  used immediately
• ProblemSome hosts/databases detect SCSI ID
  change of clones which prevent immediate database
  start on lunclones.

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Agenda

• Scope of Work
• Environment
• Workflow
• Caution with Igroups
• Implementation Workflow (Test Environment)
• Implementation Workflow
• Implementation Snap Creation/Deletion,LUN
  Destroy
• Implementation Lun Cloning
• Demonstration

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Scope of Work

• Customer wants a snapshot-scheduled automated
  fallback solution for the Informix database
• snapshots-based lun clones connected to fallback
  database transparently
• Fast fallback activation needed if necessary

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Environment

• Solaris Servers are SAN connected to NetApp
  Storage System
• Informix Database uses LUNs as raw device pool
• nightly-created LUNClones connected to Fallback
  Informix Database on Fallback Solaris Server
  (secondary)
• Fallback Solaris Server must not rescan for new
  devices when connected to LUNCLONES (no new SCSI
  IDs)

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Environment
FAS6200
Informix on Solaris - primary
FC LUNsInformix raw devices
Informix on Solaris - secondary(Fallback
nightly)
nightlycloning
FC LUNCLONEs Informix raw deviceswith same LUN
serial number
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Workflow

• stop fallback Informix DB (secondary)
• delete old snapshot (containing LUNCLONEs created
  24h ago)
• stop Informix DB (nightly at 0100 AM) on primary
• create snapshot of Volume containing Informix
  raw device LUNs (primary)
• restart Informix DB on primary (nightly at
  0101 AM)
• create clones of raw device LUNs based on new
  snapshot
• copy LUN serial numbers to clones, so the SCSI
  IDs dont change (LUNCLONEs must be offline for
  this)
• take LUNCLONEs online
• start fallback Informix DB (secondary) with
  lunclones of new snapshot

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Caution with Igroups
Lun1SR 10123
Igroup1
Due to the same serialnumber (SR) Lun1 and Lun2
are the same Lun for the filesystem (same SCSI
ID). Connecting Igroup1 to Lun2 could cause
severe damage (data loss, inconsistent LUN)
/dev/rdsk/c0d010123

• Lun2 (clone)SR 10123

Igroup2
/dev/rdsk/c0d010123
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Implementation Workflow (Test Environment)

• create volume vol create vol_naptest1 -s none
  aggr0 2genable deleting non-recent snapshots
  (busy snapshot problem)vol options vol_naptest1
  snapshot_clone_dependency on
• create 2 test lunslun create -s 100m -t linux
  /vol/vol_naptest1/lun1.lunlun create -s 100m -t
  linux /vol/vol_naptest1/lun2.lun
• create 2 Igroups
• igroup create -i -t linux igroup1
  iqn.1991-05.com.linuxkronenbourg.brauerei.local
• igroup create -i -t linux host2
  iqn.1991-05.com.linuxkronenbourg2.brauerei.local
• in production connect luns to informix server

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Implementation Workflow
stop secondary Informix DB destroy lunclones
and delete old snapshot (backing
lunclones)Lun_destroy_all_in_Volume.pl,
snap_delete.pl
stop primary Informix DB create snapshot
for lun cloning./snap.pl korn vol_naptest1
snap1 restart primary Informix DB
create clones based on this snapshot snap1 for
igroup1 (igroup1 secondary),map clones to
igroup1./lunclone.pl korn vol_naptest1 snap1
igroup1
24 hours later delete clones in Volume
vol_naptest1./Lun_destroy_all_in_Volume.pl korn
vol_naptest1 Delete snapshot backing clones
./Snap_delete.pl korn vol_naptest1
snap1 Restart Workflow
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Implementation Snap Creation/Deletion, LUN
Destroy

• out s-gtinvoke("snapshot-create",
  "volume",vol, "snapshot",snapname)
• out s-gtinvoke("snapshot-delete",
  "volume",vol, "snapshot",snapname)
• outs-gtinvoke("lun-destroy ,
  "path","clone_lunpath","force","true")

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Implementation Lun Cloning
getting parent luns of a volume
_at_lunsget_lun_from_vol()
Check if provided IGROUP is mapped to
LUNcheck_if_lun_mapped_to_igroup
create clone lun path (prefix of clone
igroupname) create_lun_path(element)(/vol/vol
1/lun1 -gt /vol/vol1/igroup1_lun1)
get serial number of parent lunlun_get_serial(
element)
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Implementation Lun Cloning
create the clone ifself lunclone_create(element
, \lunhash )
take clone offline lun_offline(lunhashclone_lu
npath)
set parent luns serial number to clone
lun_set_serial(lunhashclone_lunpath,lunhashs
erial)
map the cloned lun to the provided igroup
lun_map(\lunhash)
take clone online lun_online(lunhashclone_lun
path)
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