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https://issues.apache.org/jira/browse/HBASE-9457?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13762532#comment-13762532
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Francis Liu commented on HBASE-9457:
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{quote}
For security, the ACL table is assigned just like a user table. It is scanned
when it is needed. If anything is wrong, the operation is retried. So we don't
need it to be available all the time. It is better to be assigned asap, but it
is not mandated. So the master can start up with no problem if the region
server holding ACL dies at this moment.
{quote}
To be more accurate ACL table is able to do this because it mirrors all it's
data in ZK. All reads go through ZK but updates are done on the table itself.
And ACL write commands are invoked by a users so failures will be reflected
back to the user so he can try again. While from the perspective of a metrics
table, updates will be done by the system itself so retries have a different
effect on the system. Which may be unacceptable in some scenarios?
{quote}
For meta, we split meta log for all previouslyFailedServers if log replay is
enabled. We don't want to split log for all failed servers before we say system
table is assigned. For meta, we have meta server shutdown handler to assign
meta again so other regions can be assigned.
{quote}
This is what I was planning HBASE-9148, will address. Essentially have a system
wal and the necessary mechanisms to support it server shutdown handler, open
region handler, etc. Does that work for you?
{quote}
If during master restarts, the sever holding a system is dead, we need to
specially handle it otherwise the system table won't be available.
{quote}
I essentially copied the assign meta logic for assign system tables. I didn't
see this logic for meta. Or did I miss that?
> Master could fail start if region server with system table is down
> ------------------------------------------------------------------
>
> Key: HBASE-9457
> URL: https://issues.apache.org/jira/browse/HBASE-9457
> Project: HBase
> Issue Type: Bug
> Components: master, Region Assignment
> Reporter: Jimmy Xiang
> Assignee: Jimmy Xiang
> Priority: Critical
>
> In the region server holding the system table is killed while master is
> starting, master will hang there waiting for system table to be assigned
> which won't happen.
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