six demon bag

Wind, fire, all that kind of thing!

2017-03-21

Verifying checksums on Windows systems - correctly

Posted here, since the Fedora people apparently can't be bothered to fix their documentation.

In January 2016 I came across this question on StackOverflow, asking about an OutOfMemory error when validating the SHA256 checksum of a Fedora ISO image. The Fedora documentation suggested reading the full file and then calculating the checksum from the bytes:

$sha256.ComputeHash([System.IO.File]::ReadAllBytes("$PWD\$image"))

Why anyone would even want to read an entire ISO image into memory for a checksum calculation is beyond me. The recommended way of doing this is to open the file as a stream and calculate the checksum on that stream:

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Posted 00:24 [permalink]

2012-11-17

Importing VMs From external Hyper-V Hosts

I've been working on a project where I needed to migrate (clone actually, in order to maintain a fallback scenario) virtual machines from external (standalone) Hyper-V hosts to a Hyper-V cluster. The external hypervisors were not members of the same domain as the cluster nodes. The networks were separated by a firewall. A trust relationship between the domains was not desired.

System Center Virtual Machine Manager 2012 (SCVMM) supports this scenario, but there are several steps that must be performed to prepare for the migration.

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Posted 20:03 [permalink]