Author: tmahanta

Back Up and Restore the Embedded vCenter Server Appliance Database

Back up the embedded vCenter Server Appliance database to protect the data stored in your vPostgres database. Prerequisite: Create the folder in which you want to create the backup file and verify that you have read and write permissions on this folder. Procedure: Caution: This procedure cannot be stopped. Stopping the script will cause inconsistencies in the vCenter Server appliance database and can prevent vCenter Server appliance from starting. Log in to the vCenter Server Appliance Linux console as root. Download the Linux backup and restore package attached to this Knowledge Base article and extract it on the Linux machine. Make a executable. For example to save the file as /tmp/ , run this command: chmod 700 /tmp/ Run the file and provide the location for the backup file. For example, if you want to save the file as /tmp/backup_VCDB.bak, run this command: python /tmp/ -f /tmp/backup_VCDB.bak When the backup completes, you see a message that the backup completed successfully.   Restore the vCenter Server Appliance vPostgres DatabaseIt may be required to copy the database to the new vCenter Server Appliance or Windows installed vCenter Server. After you back up the embedded vPostgres database, you can restore it from the backup file. Note: Using WinSCP on the vCenter Server Appliance may fail. For more information, see Error when uploading files to vCenter Server Appliance using WinSCP (2107727). Prerequisite: Back up the vCenter Server Appliance embedded vPostgres...

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vSAN encryption

vSAN can perform data at rest encryption. Data is encrypted after all other processing, such as deduplication, is performed. Data at rest encryption protects data on storage devices, in case a device is removed from the cluster. Using encryption on your vSAN cluster requires some preparation. After your environment is set up, you can enable encryption on your vSAN cluster. vSAN encryption requires an external Key Management Server (KMS), the vCenter Server system, and your ESXi hosts. vCenter Server requests encryption keys from an external KMS. The KMS generates and stores the keys, and vCenter Server obtains the key IDs from the KMS and distributes them to the ESXihosts. vCenter Server does not store the KMS keys, but keeps a list of key IDs. Design Consider these guidelines when working with vSAN encryption. Do not deploy your KMS server on the same vSAN datastore that you plan to encrypt. Encryption is CPU intensive. AES-NI significantly improves encryption performance. Enable AES-NI in your BIOS. The witness host in a stretched cluster does not participate in vSAN encryption. Only metadata is stored on the witness host. Establish a policy regarding core dumps. Core dumps are encrypted because they can contain sensitive information such as keys. If you decrypt a core dump, carefully handle its sensitive information. ESXi core dumps might contain keys for the ESXi host and for the data on it. Always use a password when you collect a vm-support bundle. You can specify the password when you generate the support bundle from the vSphere Client or using the vm-support command. The...

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Owner Abdication in VSAN

When the virtual machines attempt a snapshot consolidation there are underlying vSAN components which undergo a change of node-ownership within the cluster. When these events happen simultaneously, various behaviors may occur: An error stating Generic Configuration Fault Error occurs when a backup is taken. An error stating the virtual machine cannot continue to run due to a problem with quiescing the guest operation system, and it might crash. Error message = “An error occurred while saving the snapshot: Failed to quiesce the virtual machine” abdicateDomOwnership public java.lang.String[] abdicateDomOwnership(java.lang.String[] uuids)                                         throws RuntimeFault,                                                java.rmi.RemoteException Abdicate ownership of DOM objects. The objects must be currently owned by this host. Which host has ownership of an object at a given point in time can be queried from QueryVsanObjects() or QueryCmmds() APIs. Abdicating ownership tears down DOM owner in-memory state. Hosts in the cluster will then compete to become the new owner of the object, similar to a host failure event. There is a short interruption of IO flow while the owner re-election is going on, but it is transparent to any consumers of the object. This API is meant as a troubleshooting and debugging tool....

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What is BufferCache in Esxi

VMware ESXi and ESX provide advanced configuration options that affect the behavior of various components. This article provides steps to review and set new advanced configuration options using several methods. VMware recommends that you set these configuration options under the direction of VMware Technical Support or a VMware Knowledge Base article. Numeric options have limited ranges (for example, 0-10). String options accept any value. Option values are not checked for validity beyond being in the proper range. Confirm all changes before applying them. Advanced configuration settings can be reviewed and modified on an ESXi/ESX host using the vSphere Web Client, vSphere Client, PowerCLI, Command-Line Interface, or local console. All options are grouped into sections. A given method may visually group the sections or separate the section and option names using a forward slash or period. Options are usually documented using the form.SectionName.OptionName When deploying virtual machines located on a non-shared storage to other ESXi hosts, the deployment occurs across the network (using NFC/hostd). This may have an impact on the file system buffer cache and exhaust the number of buffers, reporting a significant delay in deployment time. Advanced Options: > Login to the host console using ‘root’ credentials >Click on Manage >From System Tab please click on ‘Advanced Settings’ To prevent this issue, relocate the virtual machine templates to a shared storage that is presented to all ESXi hosts....

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VSAN calculator

The best sizing tool for VSAN: Quote from the site: The purpose of this tool is to help determine the hardware specifications for hosts in a Virtual SAN cluster required to run a set of virtual machines defined by a set of input characteristics. These important assumptions should be understood before using this tool: All hosts in the cluster are assumed to have an identical hardware profile, i.e. numbers of hard drives and flash devices, amount of physical RAM, and number of CPU cores All virtual machines are assumed to be identical in storage characteristics, i.e. number of VMDKs, size of VMDKs (assumed identical for all disks), number of snapshots, and virtual memory size All virtual machines are assumed to have the same Virtual SAN policy, i.e. number of failures to tolerate and number of disk stripes per object The tool is designed so that you can easily vary inputs to see the impact on the sizing output, thus allowing you to iterate manually for more sophisticated analyses. So now the question is how does it work??? Calculation of IOPS is a VSAN cluster is one of the most asked questions.O n the calculator, You can input how many VMs in the cluster, average VMs/Host, and some parameters for per-VM profiling. Then, it can tell you how many IOPS your cluster needs. For Server Virtualization: Total IOPS Required...

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