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Troubleshooting No Slot Available Errors in Groundplex with Mixed RAM Nodes and Max Slot Settings

·Sep 23, 2026 09:41 AM·

Hi Everyone I have question around Groundplex which has 2 feeder and 3 jcc node. The feeder node has 8gb and JCC has 16gb RAM. Initially we were seeing uneven traffic request distribution across nodes and capture max file descriptor, swap space were not uniform. So we have changed and adopted recommendation value. We have kept Max Slot 4000. And since max slot is setup on Snaplex level the feeder node also have 4k config. The Snap official document says for 8Gb Ram it is 2k slot recommend and for 16gb it is 4k. The problem is that we are sometime observing "No Slot available" error or trigger pipeline not getting invoke. Can someone help here.

5 comments

· Sorted by Oldest

Marwen M.
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Hi snohapatra1, First, the FeedMaster nodes receive and distribute requests, particularly for Ultra Tasks. The most important step is to investigate is whether your JCC nodes have sufficient available slots and memory at the exact moment the failed request arrives. The "No Slot available" might be caused by several things: Long-running pipelines are holding execution slots. What I would first check within the pipelines;
Do they trigger plenty of child pipelines via Pipeline Execute Snap ?
If so what are the selected settings for the Pipeline Execute Snap? (better pick "Local Snaplex" if relevant)
Do the pipelines contain a lot of snaps ? (especially CPU/memory intensive snaps)
✅1
smohapatra1
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Marwen M. yes I did check and made that setting change , which is under observation now. But is slot affected in feeded node too?
Marwen M.
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smohapatra1 Yes, the FeedMaster is involved in receiving and distributing the requests, but the pipeline execution slots are consumed on the JCC nodes. In your case, the important point is that Max Slots is configured at the Snaplex level, so setting it to 4,000 means the 8-GB JCC also has the same 4,000-slot configuration. Since SnapLogic recommends around 2,000 slots for an 8-GB node and 4,000 for a 16-GB node, the 8-GB JCC may be over-provisioned from a slot perspective. If that node receives enough concurrent executions, it can run into memory/resource pressure even though the configured slot limit has not been reached. I would therefore check the JCC metrics at the exact time of the "No Slot Available" error:
Which JCC received the request?
How many slots were in use on that JCC?
Was the 8-GB JCC under memory or swap pressure?
Were there long-running pipelines occupying slots?
Was traffic being distributed evenly across the JCCs?
Also, if the 3 JCC nodes are a mix of 8 GB and 16 GB, I would verify the SnapLogic guidance around keeping JCC nodes consistently sized/configured rather than relying on one Snaplex-level Max Slots value for different-sized JCCs. => So, to answer your question directly: the FeedMaster distributes the request, but the "No Slot Available" condition should be investigated primarily at the JCC execution-node level. In your topology, the 4,000-slot setting on the 8-GB JCC is something I would specifically investigate.
smohapatra1
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Marwen M. You got misunderstand, Feed node has 4k slot where its RAM is 8gb. The JCC has 16gb ram. The slot remain same across both JCC and feeder as it is config on Snaplex property level.
Michael S.
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Hi smohapatra1, since this appears to be intermittent and specific to the your Groundplex configuration, I think it would be worthwhile to have our Support team take a closer look at the environment and node metrics. I see you've opened a case with us and I'm happy to help track it from our side. Thank you.

Marwen M.
·
·
Hi snohapatra1, First, the FeedMaster nodes receive and distribute requests, particularly for Ultra Tasks. The most important step is to investigate is whether your JCC nodes have sufficient available slots and memory at the exact moment the failed request arrives. The "No Slot available" might be caused by several things: Long-running pipelines are holding execution slots. What I would first check within the pipelines;
Do they trigger plenty of child pipelines via Pipeline Execute Snap ?
If so what are the selected settings for the Pipeline Execute Snap? (better pick "Local Snaplex" if relevant)
Do the pipelines contain a lot of snaps ? (especially CPU/memory intensive snaps)
✅1
smohapatra1
·
·
Marwen M. yes I did check and made that setting change , which is under observation now. But is slot affected in feeded node too?
Marwen M.
·
·
smohapatra1 Yes, the FeedMaster is involved in receiving and distributing the requests, but the pipeline execution slots are consumed on the JCC nodes. In your case, the important point is that Max Slots is configured at the Snaplex level, so setting it to 4,000 means the 8-GB JCC also has the same 4,000-slot configuration. Since SnapLogic recommends around 2,000 slots for an 8-GB node and 4,000 for a 16-GB node, the 8-GB JCC may be over-provisioned from a slot perspective. If that node receives enough concurrent executions, it can run into memory/resource pressure even though the configured slot limit has not been reached. I would therefore check the JCC metrics at the exact time of the "No Slot Available" error:
Which JCC received the request?
How many slots were in use on that JCC?
Was the 8-GB JCC under memory or swap pressure?
Were there long-running pipelines occupying slots?
Was traffic being distributed evenly across the JCCs?
Also, if the 3 JCC nodes are a mix of 8 GB and 16 GB, I would verify the SnapLogic guidance around keeping JCC nodes consistently sized/configured rather than relying on one Snaplex-level Max Slots value for different-sized JCCs. => So, to answer your question directly: the FeedMaster distributes the request, but the "No Slot Available" condition should be investigated primarily at the JCC execution-node level. In your topology, the 4,000-slot setting on the 8-GB JCC is something I would specifically investigate.
smohapatra1
·
·
Marwen M. You got misunderstand, Feed node has 4k slot where its RAM is 8gb. The JCC has 16gb ram. The slot remain same across both JCC and feeder as it is config on Snaplex property level.
Michael S.
·
·
Hi smohapatra1, since this appears to be intermittent and specific to the your Groundplex configuration, I think it would be worthwhile to have our Support team take a closer look at the environment and node metrics. I see you've opened a case with us and I'm happy to help track it from our side. Thank you.