While benchmarking a Win10 VM in PVE 6.3-4 with CrystalDiskMark I got kernel panics (Out of Memory). This happend every time I tried the benchmark. Looking at
I had all my VM's already set to
'Host Page Cache' works fine, but ZFS 'Disk Write Cache' is just consuming RAM without limit, until an unavoidable crash. Is there any way to limit ZFS Disk Write Caching on RAM memory to a certain GB limit? It could certainly contribute to the speed of small writing processes. Otherwise this feature seems useless to me.
htop it was surely a RAM memory related issue. I first thought it was an over-assigning problem with my memory to VM's or a ballooning issue. But after I found this thread on Reddit it had to do with Disk Write Cache instead if VM memory.I had all my VM's already set to
cache=none, but this wasn't doing the trick. Setting cache=writethrough or cache=directsync did however solve my host crashing memory problems. Looking at this nice table, I thought 'Disk Write Cache' was the actual cache hardware of my HDD's. Is my (renewed) understanding correct that 'Disk Write Cache' here is actually the software (RAM) cache of ZFS? Since the Proxmox host is not directly in charge of the raw HDD's, because of the ZFS-layer in between.'Host Page Cache' works fine, but ZFS 'Disk Write Cache' is just consuming RAM without limit, until an unavoidable crash. Is there any way to limit ZFS Disk Write Caching on RAM memory to a certain GB limit? It could certainly contribute to the speed of small writing processes. Otherwise this feature seems useless to me.
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