[HBASE-5859] Optimize the rolling restart script

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Not A Problem
• Affects Version/s: 0.95.2
• Component/s: regionserver, scripts
• Assignee: Unassigned
• Reporter: Nicolas Liochon
• Created: 23/Apr/12 16:32
• Updated: 13/Jun/22 16:32
• Resolved: 11/Apr/15 01:27

Description

There is a graceful_stop script. This algorithm:

for i = 0 to servers.size {
 regionsInServer = servers[i].regions
 move servers[i].regions to random
 stop servers[i]
 start servers[i]
 move regionsInServer to servers[i] //filled back with the same regions
}

It would be possible to optimize it while keeping data locality with

for i = 0 to servers.size {
 start servers[i*2+1] on the computer of servers[i] // Two RS on the same box
 move servers[i].regions to servers[i*2+1]  // The one on the same box
 stop servers[i]
}

There would be an impact with a fixed port configuration. To fix this, we could:

• use a range of port instead of a single port. This could be an issue for the web port.
• start on a port then reuse the fixed ones when they become available. This is not very elegant if a client code is already using the previous code. Moreover the region server code is written in the meta table.
• do a mix of the two solutions: a range for the server itself, while waiting for the web port to be available.

To be discussed...

Issue Links

• is required by: HBASE-5843 Improve HBase MTTR - Mean Time To Recover