Q. i need to understand the various equipment used at a data center. what are the various regular processes and what is the irregular work? which are the good brands for equipment and which software are better?
A. thats an incredibly vague question. (no offense, just the nature of a data center makes this vague) i work in a data center...
Equipment run are servers, large A/C units, backup batteries, backup generator, and includes electromagnetic shielding or thick concrete walls, etc.
regular processes are routine drive light and error light checks, temperature monitoring, upgrading servers, or adding servers to a farm, replacing bad components, automatic scheduled test cycles on teh backups batteries and generator, load testing for the generator, load evaluation on servers and the server network, etc.
irregular work might would include replacing communication racks, server racks, replacing cabling, having to physically attach a monitor to older servers for diagnosis, maintainence on automated data backup systems, restoring from backup (due to major failure of a server or SAN, usually fault tolerance or automated recovery can take care of this).
good equipment is entirely dependent on what your doing. Cisco and Nortel are excellent networking manufacturers, i prefer Cisco, but best to stick with one brand. servers will vary depending on what your doing, Dell, HP, IBM, etc. we prefer ESX for SAN management and VMware for virtualization.
Be sure you have good cooling, i know Dell offers a program that calculates how many BTU's of heat Dell server produce, and you need at least that much cooling to counteract that heat.
Good quality cabling (systemax, etc.) is advised because you wont want to keep upgrading your network cables due to age (shoot for upgrade for prerformance here) when avoidable.
very important - remote access controllers are great, they require an additional netowrk connection but you can remote into a system and manage it without having a monitor, you can see errors and adjsut the bios without having to attach a monitor or physically touch the server.
Equipment run are servers, large A/C units, backup batteries, backup generator, and includes electromagnetic shielding or thick concrete walls, etc.
regular processes are routine drive light and error light checks, temperature monitoring, upgrading servers, or adding servers to a farm, replacing bad components, automatic scheduled test cycles on teh backups batteries and generator, load testing for the generator, load evaluation on servers and the server network, etc.
irregular work might would include replacing communication racks, server racks, replacing cabling, having to physically attach a monitor to older servers for diagnosis, maintainence on automated data backup systems, restoring from backup (due to major failure of a server or SAN, usually fault tolerance or automated recovery can take care of this).
good equipment is entirely dependent on what your doing. Cisco and Nortel are excellent networking manufacturers, i prefer Cisco, but best to stick with one brand. servers will vary depending on what your doing, Dell, HP, IBM, etc. we prefer ESX for SAN management and VMware for virtualization.
Be sure you have good cooling, i know Dell offers a program that calculates how many BTU's of heat Dell server produce, and you need at least that much cooling to counteract that heat.
Good quality cabling (systemax, etc.) is advised because you wont want to keep upgrading your network cables due to age (shoot for upgrade for prerformance here) when avoidable.
very important - remote access controllers are great, they require an additional netowrk connection but you can remote into a system and manage it without having a monitor, you can see errors and adjsut the bios without having to attach a monitor or physically touch the server.
How are snapshots used in a virtual environment?
Q.
A. Creating a snapshot
When creating a snapshot, there are several options you can specify:
Name: This is used to identify the snapshot.
Description: This is used to describe the snapshot.
Memory: If the <memory> flag is 1 or true, a dump of the internal state of the virtual machine is included in the snapshot. Memory snapshots take longer to create.
Quiesce: If the <quiesce> flag is 1 or true, and the virtual machine is powered on when the snapshot is taken, VMware Tools is used to quiesce the file system in the virtual machine. Quiescing a file system is a process of bringing the on-disk data of a physical or virtual computer into a state suitable for backups. This process might include such operations as flushing dirty buffers from the operating system's in-memory cache to disk, or other higher-level application-specific tasks.
Note: Quiescing indicates pausing or altering the state of running processes on a computer, particularly those that might modify information stored on disk during a backup, to guarantee a consistent and usable backup.
When a snapshot is created, it is comprised of these files:
<vm>-<number>.vmdk and <vm>-<number>-delta.vmdk
A collection of .vmdk and -delta.vmdk files for each virtual disk is connected to the virtual machine at the time of the snapshot. These files can be referred to as child disks, redo logs, or delta links. These child disks can later be considered parent disks for future child disks. From the original parent disk, each child constitutes a redo log pointing back from the present state of the virtual disk, one step at a time, to the original.
Note: The <number> value may not be consistent across all child disks from the same snapshot. The file names are chosen based on filename availability.
<vm>.vmsd
The .vmsd file is a database of the virtual machine's snapshot information and the primary source of information for the snapshot manager. The file contains line entries which define the relationships between snapshots as well as the child disks for each snapshot.
<vm>Snapshot<number>.vmsn
These files are the memory state at the time of the snapshot.
Note: The above files will be placed in the working directory by default in ESX/ESX 3.x and 4.x. This behavior can be changed if desired. For more information on creating snapshots in another directory, see Creating snapshots in a different location than default virtual machine directory (1002929). In ESXi 5.x and later snapshots descriptor and delta VMDK files will be stored in the same location as the virtual disks (which can be in a different directory to the working directory). To change this behavior, see Changing the location of snapshot delta files for virtual machines in ESXi 5.0 (2007563)
What products use the snapshot feature?
In addition to being able to use snapshot manager to create snapshots, snapshots are used by many VMware and third-party products and features. Some VMware products that use snapshots extensively are:
VMware Data Recovery
VMware Lab Manager
How do snapshots work?
Our VMware API allows VMware and third-party products to perform operations with virtual machines and their snapshots. This is a list of common operations that can be performed on virtual machines and snapshots using our API:
CreateSnapshot: Creates a new snapshot of a virtual machine. As a side effect, this updates the current snapshot.
RemoveSnapshot: Removes a snapshot and deletes any associated storage.
RemoveAllSnapshots: Remove all snapshots associated with a virtual machine. If a virtual machine does not have any snapshots, then this operation simply returns successfully.
RevertToSnapshot: Changes the execution state of a virtual machine to the state of this snapshot.
(vSphere 5.0 only) Consolidate: Merges the hierarchy of redo logs.
VMware vCenter and the VMware Infrastructure Client (Snapshot Manager, Storage vMotion)
When creating a snapshot, there are several options you can specify:
Name: This is used to identify the snapshot.
Description: This is used to describe the snapshot.
Memory: If the <memory> flag is 1 or true, a dump of the internal state of the virtual machine is included in the snapshot. Memory snapshots take longer to create.
Quiesce: If the <quiesce> flag is 1 or true, and the virtual machine is powered on when the snapshot is taken, VMware Tools is used to quiesce the file system in the virtual machine. Quiescing a file system is a process of bringing the on-disk data of a physical or virtual computer into a state suitable for backups. This process might include such operations as flushing dirty buffers from the operating system's in-memory cache to disk, or other higher-level application-specific tasks.
Note: Quiescing indicates pausing or altering the state of running processes on a computer, particularly those that might modify information stored on disk during a backup, to guarantee a consistent and usable backup.
When a snapshot is created, it is comprised of these files:
<vm>-<number>.vmdk and <vm>-<number>-delta.vmdk
A collection of .vmdk and -delta.vmdk files for each virtual disk is connected to the virtual machine at the time of the snapshot. These files can be referred to as child disks, redo logs, or delta links. These child disks can later be considered parent disks for future child disks. From the original parent disk, each child constitutes a redo log pointing back from the present state of the virtual disk, one step at a time, to the original.
Note: The <number> value may not be consistent across all child disks from the same snapshot. The file names are chosen based on filename availability.
<vm>.vmsd
The .vmsd file is a database of the virtual machine's snapshot information and the primary source of information for the snapshot manager. The file contains line entries which define the relationships between snapshots as well as the child disks for each snapshot.
<vm>Snapshot<number>.vmsn
These files are the memory state at the time of the snapshot.
Note: The above files will be placed in the working directory by default in ESX/ESX 3.x and 4.x. This behavior can be changed if desired. For more information on creating snapshots in another directory, see Creating snapshots in a different location than default virtual machine directory (1002929). In ESXi 5.x and later snapshots descriptor and delta VMDK files will be stored in the same location as the virtual disks (which can be in a different directory to the working directory). To change this behavior, see Changing the location of snapshot delta files for virtual machines in ESXi 5.0 (2007563)
What products use the snapshot feature?
In addition to being able to use snapshot manager to create snapshots, snapshots are used by many VMware and third-party products and features. Some VMware products that use snapshots extensively are:
VMware Data Recovery
VMware Lab Manager
How do snapshots work?
Our VMware API allows VMware and third-party products to perform operations with virtual machines and their snapshots. This is a list of common operations that can be performed on virtual machines and snapshots using our API:
CreateSnapshot: Creates a new snapshot of a virtual machine. As a side effect, this updates the current snapshot.
RemoveSnapshot: Removes a snapshot and deletes any associated storage.
RemoveAllSnapshots: Remove all snapshots associated with a virtual machine. If a virtual machine does not have any snapshots, then this operation simply returns successfully.
RevertToSnapshot: Changes the execution state of a virtual machine to the state of this snapshot.
(vSphere 5.0 only) Consolidate: Merges the hierarchy of redo logs.
VMware vCenter and the VMware Infrastructure Client (Snapshot Manager, Storage vMotion)
How to do Mac data recovery?
Q. In my mac book I in installed VMware to run Windows XP. Yesterday I accidentally removed some files from document folder in mac. Now I'm not able to run XP using VMware. How can I resolve this problem? If I reinstall VMware, can I still access my XP from Mac?? Please help
A. Data Recovery Mac - Macintosh Data Recovery is the best software program for recovery from Mac PC.
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