Before you begin
- A Super Administrator or platform operator, to decide in Review settings or to change the Global value
- Tenant administrators can still set the batch size for their own tenant or host pool in the Configuration Matrix
What changes if you choose the new default
The batch size is either a number of hosts (for example 4) or a percentage of the pool (for example 10%). A percentage is rounded up and is always at least one host. With the new default of 10%:
- A 20-host pool rebuilds 2 hosts per cycle
- A 100-host pool rebuilds 10 hosts per cycle
- A 500-host pool rebuilds 20 hosts per cycle, the most any pool rebuilds at once whatever the setting says
- A pool of 10 hosts or fewer rebuilds one host at a time
Why it matters
A fixed 4 hosts per cycle takes most of a day to bring a large pool onto a new image: a 500-host pool needed about 21 hours. Sizing the batch as a share of the pool keeps small pools gentle and lets large pools finish in a few hours.
What stays the same
- Only idle hosts are rebuilt, so nobody is signed out to make room for a rebuild
- Hosts are still held back so the pool keeps its autoscale minimum available
- The rest of the outdated hosts are picked up on the following cycles
How to decide
- Open Settings → Matrix. If the update left settings for you to review, the Review settings page opens on its own (or follow the banner at the top of the app).
- Under Automatic Re-Image Batch Size, choose Keep current behavior to stay on 4 hosts per cycle, or Use the new default to switch to 10%.
- Click Save decisions. The choice is saved at Global, so every tenant and host pool that inherits picks it up. Tenants and pools with their own value keep it.
Neither fits? After saving, set any number from 1 to 20 or any percentage in the Global column of the Configuration Matrix, or override it on a single host pool.