Timeline for Does the MongoDB background flush (MMAP) update the entire document even if only a small portion has changed? i.e. set on an array position
Current License: CC BY-SA 3.0
6 events
| when toggle format | what | by | license | comment | |
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| Sep 17, 2015 at 2:33 | answer | added | Joe Enzminger | timeline score: 0 | |
| Jun 17, 2015 at 7:51 | comment | added | King Roger | Just to add, the system is a replica set running in Azure on Windows 2012 R2 Standard A3 VM instances with 4 striped drives for the data folder. Claimed performance is 500 IOPS per disk. | |
| Jun 17, 2015 at 7:20 | comment | added | King Roger | We are running 3.0.3. Most of our problems seemed to start when we upgraded to 3.0 but it could just be coincidence as our flush times looked to have been increasing exponentially over the past few months. Going by MMS, our flush times track network, opcounters and page faults (Windows). Curiously, even overnight when the input to our system is very low we still get background flush times of a second or two. We have read that any times over a second or so are bad, so its concerning that even when almost idling we exceed these times. At the peak times of day it's as high as 30 seconds. | |
| Jun 16, 2015 at 13:05 | comment | added | Stennie | What specific version of MongoDB and O/S are you using, and what sort of storage config (file system & disk type)? Also, how long are your average flush times? Flush times are only part of the overall picture so in isolation it's hard to guess what the problem might be. Are you using a monitoring service like MMS? If so, are there any other metrics that appear to correlate with your long flush times? | |
| Jun 16, 2015 at 6:31 | answer | added | Stennie | timeline score: 1 | |
| Jun 15, 2015 at 13:16 | history | asked | King Roger | CC BY-SA 3.0 |