Redis 2.8.4 creates a 8GB file on startup named "RedisQFork_1628.dat" #83

dionoid opened this Issue Apr 4, 2014 · 8 comments


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dionoid commented Apr 4, 2014

The creation of this file was introduced just recently (somewhere in the commits of april 1st - april 4th). This doesn't seem right.


Redis uses the fork() UNIX system API to create a point-in-time snapshot of the data store for storage to disk. This impacts several features on Redis: AOF/RDB backup, master-slave synchronization, and clustering. Windows does not have a fork-like API available, so we have had to simulate this behavior by placing the Redis heap in a memory mapped file that can be shared with a child(quasi-forked) process. By default we set the size of this file to be equal to the size of physical memory. In order to control the size of this file we have added a maxheap flag. See the Redis.Windows.conf file in msvs\setups\documentation (also included with the NuGet and Chocolatey distributions) for details on the usage of this flag.

dionoid commented Apr 7, 2014

Thanks for explaining this.

@dionoid dionoid closed this Apr 7, 2014

How can i move this file to disk D:/ ?


You can starting with 2.8.12, using the heapdir config setting. Recent releases are here:, in addition to nuget and chocolatey.


Wow. I just discovered this is the reason why my hard drive is always full--6 of these files, taking up almost 40GB, after about 30 minutes of playing around with Redis at a hackathon install fest. I didn't see them in my WinDirStat analyses because I neglected to run as admin. They also remained on my drive after uninstalling Redis. Is there a warning about this somewhere in the install docs? I didn't see one in my quick scan.

vaasha commented May 9, 2016

Can I delete these QFork files? They took 60% of my drive capacity and they seem to claim 2GB a day, even though I did not add any single key to Redis DB for a while.


Hi @vaasha
yes, the files can be deleted when Redis is not running.
Version 2.8.2400 should already take care of auto-cleaning those files.

vaasha commented May 9, 2016

Thank you, I'll upgrade to the newer version which was not done for a while, since I didn't use the application using redis for a while.

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