[pve-devel] [PATCH qemu-server] qcow2: increase cache-size to 1GB
DERUMIER, Alexandre
alexandre.derumier at groupe-cyllene.com
Fri Oct 3 16:05:23 CEST 2025
> >
>>But the max value might even be reached for relatively small disks.
>>And
>>there are users that have a lot of VMs with rather small disks. For
>>them, the increase in memory consumption would be quite big I
>>suppose!
Currently the qemu default cache size is 32MB , enough to handle 256 GB
images.
so, I'm not sure It'll make so much difference. even if user have a lot
of 512GB images (100images for example), 50TB, it'll add an extra
100x32MB = 3GB memory .
sure, if user have 100 imagesx8TB, 800TB stockage on 1 host, It'll
increase memory to around 100x1GB = 100Gb memory. ^_
>>Yes, I'd also be in favor of using something calculated from the
>>size.
>>We could additionally add a drive configuration option to override
>>the
>>value if we really want to.
and if we use something calculated from the size of the disk, it'll not
help to limit global memory usage.
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