OpenStack Object Storage (swift)

Strange delay in account server POST

Asked by David Kranz

My swift system is not under very heavy load. An application is running that does frequent account POSTs to set the tempurl metadata. Usually this operation in the account servers log shows it taking about .00x seconds. But every few hundred requests or so, spread over hours, this request will take up to 7 seconds to complete. I looked at the account server code and didn't see anything that could plausibly take that long. Is there any known explanation for this? If not, is there some more instrumentation that can be turned on to find out why this is happening?

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Chuck Thier (cthier) said : 		#1

The first step in debugging this issue would be to get the transaction ID from the headers returned for the slow request. Then grep all the backend server logs for that transaction id. Each back end request log line includes how long that request took, and you can also look for any errors or time-outs that may have caused the issue.

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