Category: ESXi

Corruption in dlmalloc 0

ESXi Fails with “Corruption in dlmalloc” on HPE Server

“Corruption in dlmalloc” issue occurs because multiple esxcfg-dumppart threads attempt to free memory which has been used for configuring the dump partition. Thread A checks if there are entries to be freed and proceeds to free them, while within the same time frame, Thread B is also attempting to free the same entries.
Based on VMware KB2147888, this issue is resolved on ESXi 6 U3. But why issue is happening on ESXi 6 U3 or ESXi 6.5 U1 when they are installed on HPE ProLiant servers?

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How to Export Big Virtual Machine as OVA or OVF

I guess, you know the instruction but let’s quick review. You can export virtual machines via some different tools such as vSphere Client, vSphere Web Client and others. All administrators do it today and familiar with OVA and OVF. It’s possible to export small virtual machines via vSphere Client, vSphere Web Client, PowerCLI. If you want to export virtual machine with 200~300 GB virtual disks (Thin or Thick), there is serious problem, just make sure that you have enough free space. But did you try to export big or monster VM as OVA or OVF?

iSCSI vs Fiber Channel 0

Guest Connected vs RAW Device Mapping (RDM)

RAW Device Mapping (RDM) is one of oldest VMware vSphere features which introduced to resolving some limitation on virtualized environments such as virtual disks size limitation and deploying services top of fail-over clustering services.

You can use a raw device mapping (RDM) to store virtual machine data directly on a SAN LUN, instead of storing it in a virtual disk file. You can add an RDM disk to an existing virtual machine, or you can add the disk when you customize the virtual machine hardware during the virtual machine creation process.

Provisioning Types Comparison 0

VMDK Write Performance on Different Provisioning Types

VMDK (Virtual Machine Disk) has been designed to mimic the operation of physical disk. Virtual disks are stored as one or more VMDK files on the host computer or remote storage device, and appear to the guest operating system as standard disk drives.

VMware supports three provisioning types:

Thin Provisioned
Thick Provisioned
Eager-zeroed Thick Provisioned