Legacy Netgear ReadyNAS models do not officially support the new ReadyNAS OS 6. Luckily is pretty straightforward to upgrade most of X86 based legacy ReadyNAS devices from RAIDiator 4.2 to ReadyNAS OS 6 unofficially. Needless to say, this is completely unsupported by Netgear and proceed at your own risk.

There are bunch of threads about this on Netgear Forums, but basic instructions can be found here.

Read more: Upgrading Netgear ReadyNAS Pro 6 from RAIDiator 4.X to ReadyNAS OS 6.X

Issue

FTP users created in Plesk Onyx control panel cannot upload files to some sub-folders inside httpdocs.

Permission denied. Critical file transfer error.

Read more: Plesk Onyx - FTP users can't write to some subfolder inside httpdocs

Issue

Some of the VMs hosted on VMware ESXi 5.5 (DELL PowerEdge T310 host) occasionally become unresponsive.
All attempts to login to the host via VMware vSphere Client fails with following error:

Could Not Connect
vSphere Client could not connect to "10.5.5.25". An unknown connection error occurred. (The request failed because the remote server took too long to respond. (The operation has timed out))

VMware console vmkernel system logs (ALT + F12) display following errors:

mptscsih:  ioc0: task abort: FAILED (sc=0x412e8182ecc0)
WARNING: LinScsi: SCSILinuxAbortCommands: 1843: Failed, Driver MPT SAS Host, for vmhba2
WARMING : ScsiPath: 6292: Set retry timeout for failed TaskMgmt abort for CmdSN   0x0, status
mptscsih:  ¡oc0: attempting task abort! (sc=0x412e81718200)

The vmbha2 refers to a RAID-1 SATA array that had all affected virtual machines hosted.

Read more: LinScsi: SCSILinuxAbortCommands: 1843: Failed, Driver MPT SAS Host, for vmhba2

PHP PEAR was not installed on my 1&1 VPS (CentOS 7) at all, so the first step was to to install it: 

yum install php-pear

Read more: Installing and enabling PEAR Mail on 1&1 Plesk VPS