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Michael
Michael

Posted on • Originally published at gbase.cn

Merging PSM Backups Across GBase 8s Nodes for Continuous onbar Recovery

#gbase #database #数据库

In a GBase 8s HAC cluster, after a failover the new primary generates its own logical log backups. If you later need to recover the original primary using a full backup, you’ll want those post‑switch logs too. This post demonstrates how to merge PSM backup catalogs from two nodes using onsmsync, so onbar -r -l can restore a continuous chain.

Setup

  • HAC pair: gbase41 (primary, dbhost01), gbase42 (standby, dbhost02)
  • GBase version: 12.10.FC4G1AEE
  • Storage manager: Built‑in GBASE PSM, backup devices at /home/gbasedbt/bak/DBSPOOL and LOGPOOL

Backup and Failure Simulation

  1. A level‑0 backup and several logical log backups (27–31) are taken on gbase41.
  2. The primary is shut down; gbase42 is promoted and generates logs 32 and 33.
  3. Manually transferring those log files and editing the ixbar file on gbase41 fails because the PSM catalog does not recognize them.

The Right Way: Export and Import PSM Objects

PSM provides onsmsync for moving backups between instances. The tested process follows IBM’s Example 4.

1. Export from the new primary (gbase42) 

onpsm -D add /home/gbasedbt/bak/psm_exportdir -g EXTPOOL -t FILE
onsmsync -E -p host02_37 -l 37
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This exports all backups (including logs up to 37 and the level‑0 image) into psm_exportdir/host02_37.

2. Copy to the original primary (gbase41) 

scp -rp host02_37 dbhost01:/home/gbasedbt/bak/psm_exportdir/
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3. On the original primary, prepare the catalog

First add EXTPOOL:

onpsm -D add /home/gbasedbt/bak/psm_exportdir -g EXTPOOL -t FILE
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Because the servers have different instance names, delete all existing PSM objects to avoid conflicts:

for i in {1..15}; do onpsm -O del -o $i -y; done
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4. Import the catalog 

onsmsync -I -p host02_37
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This registers all objects from the export, rewrites ixbar.0, and associates them with gbase41.

5. Run the recovery 

onbar -r -p   # physical restore
onbar -r -l   # logical restore – rolls forward from log 34 to 37
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The logical restore completed up to log 37 — a fully continuous chain, proving the merge works.

Key Takeaway

  • onbar is a client that feeds data to the storage manager; PSM keeps its own catalog. Directly combining file copies isn’t supported.
  • Use onsmsync export/import to legally merge backups from two nodes in a gbase database environment. This is the documented IBM method.
  • For simpler multi‑instance backup merging, consider ontape (which bypasses PSM) or consult third‑party backup vendors like DingJia.

With this approach, you can maintain a consistent disaster‑recovery story even after role switches in your GBASE high‑availability setups.

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