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[ale] Low entropy on vm
- Subject: [ale] Low entropy on vm
- From: mike at trausch.us (Michael B. Trausch)
- Date: Fri, 18 Sep 2015 17:17:22 -0400
- In-reply-to: <CAEo=5PytmKZdMUomYvkDvCYg3iO7Cn0fcO6vGPKU7ShPDN9uuw@mail.gmail.com>
- References: <CAEo=5PytmKZdMUomYvkDvCYg3iO7Cn0fcO6vGPKU7ShPDN9uuw@mail.gmail.com>
On Fri, 2015-09-18 at 11:17 -0400, Jim Kinney wrote:
> User was trying to transfer data to/from oracle on Linux. The
> connection kept dropping. The Linux system is a vm on ESXi. The
> physical host is a tad overloaded on memory not complaining about cpu
> cycles.
> By telling oracle to use /dev/urandom instead of /dev/random, the
> connection drops went away.
> Could the vm be not getting enough cpu cycles to keep entropy pool
> full or should I look somewhere else? Ideas to boost entropy
> collection rate are appreciated.
When using the QEMU/KVM stack, the solution is to have a really strong
HWRNG on the host, and pass through some of that entropy to the guests.
I don't know if there is a way to do that on the stack that you're
asking about, though.
If you have a R? or R?2 laying around, install a barebones buildroot
with rngd, openssh, and a set of ssh keys, and use its HWRNG to feed
the VM. The HWRNG will generate random data far faster than a typical
desktop or server will. (The /dev/random device then responds more like
the /dev/urandom one does, but with more entropy.)
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