Friday, March 30, 2012

VCB Proxy

A Windows application that provides a LAN-free fiber Channel or iSCSI-based backup solution that offloads the backup processing to a dedicated physical server.
VCB takes advantage of the snapshot functionality of ESX server to mount the snapshots into the file system of the dedicated VCB server.

Once the respective VM files are monted, entire VM or individual files can be backed up using third-party tools. VCB scripts integrate with serveral third-party back-up solution to provide a means of automating the backup process.

  • Turning off automount before connecting to SAN
  • Using one HBA, and disable other HBAs if any
  • Add path at environmental variable for easy command-line
  • Licensing VCB from client

V2P

http://www.vmware.com/support/v2p/
  • Only covers the details from Windows OS
  • Not supported by VMware
For Linux environments, the imaging tool (CloneZilla Live) is a reasonable choice.
Ghost 11.5 or above also support vmdk file to disk
Acronis True Image

Linux V2P

(Credit to: http://pleasedonttouchthescreen.blogspot.com/2011/08/linux-v2p.html)

Virtualization may be the best thing since the microprocessor itself, but sometimes you may have to backtrack your own footsteps.
Here are the steps to convert a Red Hat 5.5 linux vm running on an ESX to a physical box:

Using a disk imaging tool, dump the vmdk of the vm to the internal disk of the target machine.Boot the physical box with the Red Hat CD in rescue mode
Do not mount any partitions, but select "continue" to jump into the shell.

Mount the restored partition:

#chroot /mnt/sysimage

edit the modules list and put every driver the physical machine needs.
you can see which drivers are needed by looking at modprobe.conf from another machine that has the same hw as the one you are V2P-ing.
if you don't have another machine, you can use the same target machine: just before imaging it with the source vmdk, install it from scratch with the Red Hat CD and take note of the resulting modprobe.conf

#vi /etc/modprobe.conf

here is the one i used as a reference (an HP machine)

options bnx2x disable_tpa=1
alias eth0 bnx2
alias eth1 bnx2
alias eth2 tg3
alias eth3 tg3
alias scsi_hostadapter cciss
alias scsi_hostadapter1 lpfc
alias scsi_hostadapter2 usb-storage

then you will have to rebuild the initrd image to include the needed drivers.
note that kernel version number must match the one used on your vm.

/sbin/mkinitrd -v -f /boot/initrd-2.6.18-164.el5.img 2.6.18-164.el5

and reboot.
at boot time you will probably get some errors on X initialization because the graphic card has changed: just answer yes at the reconfigure option and select 800x600 as default resolution.

P2V V2V

 VMware converter is the background tool to completed the task: P2V assistant + VMware importer; disk size could be changed during the migration process
  • Live/hot Migration
  1. Guided Consolidation at vCenter : VMware Capacity Planner Service as the background process (Start the live migration process from consolidation plan by running VMware converter as tasks)
  2. Just use the import Machine option from vCenter client with VMware converter plugin
  3. From stand-alone VMware converter to select the physical box to be migrated.
  • Cold Migration
       Conversion of a powered off physical box
       Need VMware vCenter converter boot CD from VMware on Download Drivers and Tools (VMware vCenter Server 4.0 Update 4 and modules->Show details)
       Cold clone is ideal for server with frequent updated data

V2V also use the VMware convert to convert also the support VM format from VMware or other third-party to desired VM format for ESX or VMplayer/Fusion/workstation.

Tuesday, March 20, 2012

Host-based replication vs. array-based replication

SRM 5.0 with array-based replication

Array-based replication

Array-based replication requires a central data storage unit (SAN or NAS) and a partner unit. With array-based replication, the SAN or NAS processes the data and the commands to process and validate the data being replicated.

Advantages of array-based replication

  • The work is offloaded from the servers to the storage device.
  • You only need one location to control many replications of multiple servers.
  • Hosts (Servers) are not required at the second site or to be attached to the second SAN/NAS.
  • A central SQL server can be set up to replicate with the servers that actually present applications to users, such as order tracking applications.
  • The right software can queue databases to ensure that transactions and the database are in a recoverable state.

Disadvantages of array-based replication

  • Cost per device can be high, especially when you’re not replicating all of the data on the SAN.
  • Only SAN or NAS based data can be replicated or controlled.
  • A second SAN or NAS is required, increasing the cost for the solution.
  • There could be compatibility problems of replication technology/software between SAN/NAS hardware and vendors.

Examples of array-based replication software


The first method we’ll look at is host-based replication. Simply put, host-based replication is replicating data and using the servers that hold or receive the data to do the work of moving the data. Host-based replication has many advantages.

Advantages of host-based replication

  • When you have a small number of servers that require data replication, you can tailor the host-based solution to meet your needs. Customization is key, since you can choose specifically what data to replicate between hosts.
  • You can make purchases as needed and phase hosts into the replication strategy.
  • You can pick and choose the data that is to be replicated (the entire server doesn’t have to be replicated).
  • You can create a schedule for sending data. Depending on the software you’re using, you can throttle bandwidth based on availability and use (i.e., you can increase it in the evenings when the WAN use is less).
  • Some solutions allow you to do a many-to-one sender/receiver replication.
  • You can have dissimilar storage solutions at each end (Local storage to SAN or NAS, etc.).

Disadvantages of host-based replication

Here are a few disadvantages to using host-based replication:
  • It requires a sender and receiver to be active on each end. This means that hardware and an OS (and possibly other applications) are required and increase your budget.
  • Both the sender and receiver hosts must have the same patch levels for the OS and applications in order to do a true recovery in times of failure.
  • With the numbers of servers replicating increases, so does their management time.
  • Not all applications can support host-based replication.

Examples of replication software

Here are a couple of replication software packages that are currently available:

Network-based replication

The last type of replication is network (or fabric) based replication. This type of replication works separately from the hosts (servers) and the storage devices. A device on the network intercepts packets being sent to and from hosts and arrays and copies them. These copies are replicated to a second device that then replays the packets at a second location. The devices are, in essence, splitters. The data goes in and then it’s split out to different sources.

Advantages of network-based replication

  • It’s a separate component from the SAN/NAS or the hosts.
  • Processing is independent to the host and SAN/NAS.
  • It allows replication between multi-vendor products.

Disadvantages of network-based replication

  • The cost of implementing devices to support this kind of replication is high.
  • Newer technology for the data center, standards, and process are still being worked out.
  • There are a limited number of “players” in this area of replication.

Examples of network-based replication products

Asynchronous or Synchronous Replication

Synchronous replication - guarantees "zero data loss" by the means of atomic write operation, i.e. write either completes on both sides or not at all. Write is not considered complete until acknowledgement by both local and remote storage.
Asynchronous replication - write is considered complete as soon as local storage acknowledges it. Remote storage is updated, but probably with a small lag. Performance is greatly increased, but in case of losing a local storage, the remote storage is not guaranteed to have the current copy of data and most recent data may be lost.

Asynchronous Replication Synchronous Replication
Data Loss By its nature there may be some data loss [1] Some solutions will guarantee no data loss [1]
Resilience 2 failures are required for there to be loss of service [2] 
Failures which lead to data corruption will not be replicated to the second copy of the data [3]
A single failure could lead to the loss of the service [2]
Failures which lead to data corruption are faithfully replicated to the second copy of the data [3]
Cost Asynchronous replication solutions are generally more cost effective Synchronous replication tends to be considerably more expensive to buy and manage than a comparable asynchronous solution [4]
Performance Less dependent on very low latency, high bandwidth network links between units of storage Dependent on very low latency, high bandwidth network links between units of storage [5]

http://sfdoccentral.symantec.com/sf/5.0/hpux/html/vvr_planning/pt_ch_planconfig_vvr10.html
Synchronous mode
Asynchronous mode
Need for Secondary to be up-to-date
Ensures that the Secondary is always current. 
If the synchronous attribute is set to override, the Secondary is current, except in the case of a network outage. 
Ensures that the Secondary reflects the state of the Primary at some point in time. However, the Secondary may not be current. The Primary may have committed transactions that have not been written to the Secondary. 
Requirements for managing latency of data
Works best for low volume of writes. 
Does not require latency protection (because the Secondary is always current). 
Could result in data latency on the Secondary. You need to consider whether or not it is acceptable to lose committed transactions if a disaster strikes the Primary, and if so, how many.  
VVR enables you to manage latency protection, by specifying how many outstanding writes are acceptable, and what action to take if that limit is exceeded.  
Characteristics of your network: bandwidth, latency, reliability
Works best in high bandwidth/low latency situations. If the network cannot keep up, the application may be impacted.  
Network capacity should meet or exceed the write rate of the application at all times. 
Handles bursts of I/O or congestion on the network by using the SRL. This minimizes impact on application performance from network bandwidth fluctuations.  
The average network bandwidth must be adequate for the average write rate of the application. Asynchronous replication does not compensate for a slow network. 
Requirements for application performance, such as response time.
Has potential for greater impact on application performance because the I/O does not complete until the network acknowledgement is received from the Secondary.  
Minimizes impact on application performance because the I/O completes without waiting for the network acknowledgment from the Secondary.  

Monday, March 12, 2012

the difference between differential and incremental backups

Differential backups were the next step in the evolution of backup strategies. A differential backup backs up only the files that changed since the last full back.

Incremental backups also back up only the changed data, but they only back up the data that has changed since the last backup — be it a full or incremental backup. 

While incremental backups give much greater flexibility and granularity (time between backups), they have the reputation for taking longer to restore because the backup has to be reconstituted from the last full backup and all the incremental backups since.

http://www.acronis.com/resource/solutions/backup/2005/incremental-backups.html

Monday, March 5, 2012

VMware Capacity Planner vs Capacity IQ

VMware Capacity Planner is an IT capacity planning tool that collects comprehensive resource utilization data in heterogeneous IT environments, and compares it to industry standard reference data to provide analysis and decision support modeling.

With the launch of the VMware vCenter Operations Management Suite and vCenter Operations Manager 5.0, capacity management functionality previously offered in vCenter CapacityIQ has been fully integrated with vCenter Operations Manager.
VMware has announced the end of availability (“EOA”) of vCenter CapacityIQ for sale as a standalone product effective January 24, 2012. VMware will continue to offer technical support and maintenance services for vCenter CapacityIQ through December 1, 2012, in line with our General Support Policy: www.vmware.com/support.

Friday, March 2, 2012

2.7 Design Backup and Availability Solutions in a Multi-site Environment

Snapshot
  • VMware Data Recovery: including a VM appliance and vCenter agent; snapshot retention and data deduplication.
  • VMware Consolidated Backup (VCB): designed for VI3, and supported with all editions of vSphere; VCB enables LAN-free backup of VM from a centralized proxy server; file level full/incremental for Windows VM backup. Physical Box has access to vCenter and LUNs that vmdk files reside.
  • vStorage API for Data Protection are the next  generation of VCB and are included with all editions of vSphere (VADP); change block tracking
  • VMware Site Recovery Manager (SRM): recovery plans and documents; a pair of remotely comunicated SRM servers; shadow VM at recovery site only will be used by SRM whereas the protected VM at protected site;  SRM plugin at vCenter; Protection group; Multiple protected sites to one recovery site; ABR (Array Based Replication) vs VR (vSphere Replication)
  • vCenter Server Heartbeat
  • HA & FT

2.5 Define Logical Security Design

Network Segmentation
  Fully trusted Zones virtualize entire datacenter, including all network and security devices.For DMZ, it is called a DMZ in a box. This configuration enables you to maximize server consolidation and realize significant cost reduction. VLANs are not required as they are in the configuration using partially collapsed trust zone with virtual separation. Minimum 3 NICs per ESX host for Internet, Internal network, and Management network. NIC teaming for redundancy is also considerate.

Virtualized TrustZone Security Checklist
  • Harden and isolate the service console and management network
  • Enforce consistency of network configuration across all hosts
  • Set Layer 2 security option for virtual switch: promiscuous mode, MAC address change, forged transmission
  • Enforce separation of duties: Roles at vCenter.
  • Use ESX resource management capabilities: reduce DoS attack
  • Regularly audit virtualized configuration.
vShield Zone
vSphere Hardening Guide