In addition to those questions that need to be answered, I've found it fairly inefficient to add only 1 node at a time.
With 2:1 protection, you should add nodes in multiples of 3. With +2 protection, you should add in multiples of 4.
The rationale is that if you're running out of space, you will not help much by adding only a single node since writes still have to go to the rest of the cluster until the space is balanced (which can take weeks in some environments). If you add 3 nodes at a time, then all new writes can be sent to the new nodes.
> The rationale is that if you're running out of space, you will not help much by adding only a single node since writes still have to go to the rest of thecluster until the space is balanced (which can take weeks in some environments). If you add 3 nodes at a time, then all new writes can be sent to the new nodes.
I don't know of any optimization in OneFS that works like this. If you're using FEC, and the file is large enough, and there is free space elsewhere on the node pool you're writing to, blocks will still go to the "old" nodes, in addition to the newly added nodes.
It's certainly true that OneFS will prefer nodes/drives with more free space, but not at the expense of writing a stripe inefficiently.
Anonymous User
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April 10th, 2015 06:00
In addition to those questions that need to be answered, I've found it fairly inefficient to add only 1 node at a time.
With 2:1 protection, you should add nodes in multiples of 3. With +2 protection, you should add in multiples of 4.
The rationale is that if you're running out of space, you will not help much by adding only a single node since writes still have to go to the rest of the cluster until the space is balanced (which can take weeks in some environments). If you add 3 nodes at a time, then all new writes can be sent to the new nodes.
kipcranford
125 Posts
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April 10th, 2015 06:00
> The rationale is that if you're running out of space, you will not help much by adding only a single node since writes still have to go to the rest of the cluster until the space is balanced (which can take weeks in some environments). If you add 3 nodes at a time, then all new writes can be sent to the new nodes.
I don't know of any optimization in OneFS that works like this. If you're using FEC, and the file is large enough, and there is free space elsewhere on the node pool you're writing to, blocks will still go to the "old" nodes, in addition to the newly added nodes.
It's certainly true that OneFS will prefer nodes/drives with more free space, but not at the expense of writing a stripe inefficiently.
Peter_Sero
4 Operator
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1.2K Posts
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April 10th, 2015 07:00
Ed, I see what you are aiming at... but wouldn't that take just "batches of at least 3" rather than "multiples of 3" (= 3, 6, 9)?
(or 4 for +2 protection resp.)
-- Peter
ayas
Community Manager
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7.4K Posts
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April 12th, 2015 17:00
hi ed and kipcranford
Thanks for the comment , Right,,,it is depends on how cluster configured ,,,Adding one node may not worth whole...
thanks !
aya
ayas
Community Manager
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7.4K Posts
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April 12th, 2015 17:00
Hi harrim10
Thanks for the reply , you are right there are so much factor involved ....That is why he asked this question to start with .
I may suggest him to your suggestion they may need to take ...
Thanks heaps!
aya
ayas
Community Manager
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7.4K Posts
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April 13th, 2015 22:00
HI everyone,,,,
FYI ... I just had some idea from other user about CPU usage and Node .
Note that this is not official and just for this particular user .... he has line with 60% usage as It will be
Average of 30% CPU usage for jobs with Impact Policy set as Medium ( like FlexProtect)
and leave some extra for unexpected ...