[Glass] Tranlogs space on Linux
Dale Henrichs via Glass
glass at lists.gemtalksystems.com
Thu Dec 17 17:58:55 PST 2015
On 12/17/2015 11:44 AM, BrunoBB via Glass wrote:
> Why i need so many tranlogX.dbf to restore a backup ?
When you make a backup, you need to keep all of the tranlogs that were
created after the backup was made ... otherwise you won't be able to
restore from your backup and the replay tranlogs to restore your system
to the state prior to crash ...
If you make a new backup you can throw all of the tranlogs associated
with the old backup and start keep tranlogs for the new backup ...
> I'm reading chapter 8 "To Initiate a Checkpoint"
> If i do:
> System startCheckpointSync.
> The tranlog will start from 0 again ? or it is just a like a commit without
> realising locks ?
no the tranlog file names increase with each new tranlog ... the stone
keeps track of the tranlog numbers it has written and the ones that it
needs to restore ...
When you restore from a backup, the last tranlog file written is
recorded, so the stone will know what tranlog is needed to restore post
> Page 54:
> "At any point, the method Repository>>oldestLogFileIdForRecovery identifies
> the oldest log file needed for recovery from the most recent
> Is System startCheckpointSync this checkpoint ?
Yes that method starts a checkpoint ...
Keep in mind that the tranlogs are used for recovery in two cases:
1. the stone crashes and you restart the tranlog - which starts at the
most recent checkpoint and then recovers from tranlogs to get the
2. the stone crashes and the extents are corrupted, so you have to
from backup in which case after restoring from the backup, you
to restore from tranlogs kept since the backup was made
(including the tranlogs
needed to restore to the checkpoint of the backup)
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