|HOME||STORAGE VIRTUALIZATION||WHITE PAPERS||CONTACT|
Network Diagram of Solution
The replicated vRanger backup volume can serve as an offsite backup, or we can choose to use that datastore to implement a traditional backup according to our backup policy. We can even use SANmelody's Snapshot option to implement disk-to-disk backups, if required.
Finally, we will test our solution, restoring VMs from the replicated volume to our DR site's ESX server.
CREATING THE SAN VOLUMES
SANmelody is a software package that implements a SAN Storage Array with native Fibre Channel and iSCSI support. SANmelody runs on a standard Windows x86 platform and can "virtualize" any storage presented to the Windows LDM (Logical Disk Manager).
Commodity SAS or SATA drives can be pooled, from which virtual volumes (or LUNs) are taken and presented over iSCSI or Fibre Channel to the storage clients our ESX hosts, SQL, Exchange and File servers, etc.
SANmelody Virtual SAN Storage is ideal for ESX Servers
The SANmelody GUI is an intuitive and easy-to-use set of snap-ins in the Windows Management Console. If you can manage a Windows server, you can manage SANmelody.
In the dialog below, a new Thin Provisioned virtual volume named "vRanger" is mapped to our VirtualCenter server which hosts vRanger PRO.
SANmelody implements the complete SCSI3 recommendation and is ideally suited to any SAN storage application, including its use for creating VMotion-enabled VMFS volumes for VMWare HA or DRS. Here, our "vRanger" volume will be used for saving vRanger PRO backups.
ESTABLISHING AN ASYNC MIRROR
Asynchronous IP Mirroring (AIM) is an optional licensed feature of SANmelody. It allows two cooperative SANmelody Storage Arrays to replicate SAN volumes over standard IP.
At our DR facility, we install a second SANmelody Storage Array, creating virtual volumes that will receive the replication from the SANmelody server at our datacenter. In this example, we create a single virtual volume which will receive the replication of our "vRanger" volume. We name the virtual volume "AD-vRanger", an arbitrary prefix to remind us that the volume is an active AIM Destination volume. We then add it to the AIM Destination Manager's list of replication volumes, as shown in the following screenshot.
At the source site, we establish an AIM relationship between the two SANmelody servers, creating a new "Destination Node". We specify the name and IP address or our SANmelody server at the DR site.
We then create the AIM relationship between our source "vRanger" virtual volume and the replication target, our "AD-vRanger" virtual volume.
Useful Tip: Normally at this point, we would need to "initialize" our mirror to bring the source and destination into synch. However, in this case, we have not yet formatted the source "vRanger" volume on the vRanger PRO server, so in effect the two volumes are in an unknown state. Formatting the volume (e.g. creating an NTFS file system) will result in the NTFS catalog being replicated to the DR site, effectively synching the two volumes.
We are now actively replicating our vRanger backup volume to the DR site.
SETTING UP THE vRANGER VOLUME
Thus far we have mapped a LUN from SANmelody to our vRanger PRO server and are actively replicating to the DR site. After a "Rescan Disks" in the Windows LDM, we discover our SANmelody volume, format it and mount it.
The Disk Properties Dialog of a SANmelody Disk
Just for the sake of clarity and organization, we create a folder called "vRanger" on the volume. This folder will be used to hold our backups.
TAKING THE BACKUPS
We install Vizioncore's vRanger PRO product on our Virtual Center server and use it to backup our VMs for replication to the DR site. vRanger features an intuitive, easy-to-use GUI, complemented by a CLI interface.
Launching the GUI, we click the "Backup VM(s)" button to prepare our backups. The Backup interface involves three screens titled "Source", "Destination" and "Options".
In the "Source" screen, we select those VMs and/or their disks that we wish to backup. For instance, we could decide to backup the relatively static "C:" drive .vmdk files for the VMs once every 2 weeks, and backup their "D:" data drive .vmdk files nightly.
Selecting VM's to Backup
After selecting the VMs targeted for backup, we navigate to the "Destination" tab to select the volume on which we want the archives to be placed in this case, the "vRanger" folder we created on our SANmelody vRanger volume.
vRanger PRO can backup the VMs to VMFS volumes, or to NFS or CIFS (i.e. SMB or Windows) shares. Backing up to a VMFS volume eliminates LAN traffic as it is a block level operation using the SAN. vRanger PRO also integrates with VCB (VMware's Consolidated Backup framework). Using vRanger with VCB will yield even faster LAN-free backups.
vRanger Includes VMWare VCB Integration
Nonetheless, most vRanger customers prefer using Windows shares as it permits taking differential backups. It also offers performance advantages over backing up to a console-based VFMS datastore.
Clicking the Options tab, we can control aspects of the backups. For instance, we can choose to automate full vs. differential backups. Taking differentials will radically improve the utilization of our inter-site bandwidth.
In the screenshot below, this vRanger backup job will take a full backup every 14 days, and take differentials in between.
Selecting vRanger Backup Options
Notice the "Encrypt Data Transfer" flag. We may use this feature to secure our data against hackers when, for example, we are backing up over an unsecured link. We'll talk more about this when we discuss offsite backups.
vRanger can also install and enable VSS agents in Windows VMs. VSS will provide application "quiescing" prior to taking the snapshot of a running VM.
After selecting options and clicking "Run Backup", the resulting archives and their associated "info" files will be placed on the SANmelody virtual volume and thus replicated via AIM to the DR center.
Active Data Replication
AUTOMATING THE BACKUP PROCESS
The vRanger PRO GUI facilitates creating CLI scripts. The selections we make in the GUI result in command lines which can easily be put into scripts and scheduled.
Copying the CLI Command to Build a Script
DataCore also provides scripting to drive its snapshot and AIM commands. We can use the AIM Snapshot command after our backups have completed to insert an in-band snapshot request into the data stream. In this way, once our backups have been replicated to the DR site, a snapshot will be enabled or incremented. We can use the snapshot to run a backup, or to set a coherency point should we need to test or use the DR site.
The batch file will look something like this:
"C:\Program Files\vizioncore\esxRanger Professional\esxRangerProCli.exe" -virtualcenter vc2://Folder=group-d1 -copylocal V:\vRanger -drives:all -totalasync 10 -hostasync 2 -lunasync 3 -vmnotes -diffratio 50 -maxfullage 14 -retendays 31 -zipname [config]_[year][month][day][hour][minute][second] -autodiff -mailonerror -vss
DCSAppRCmd -c \\tussmya "AIMSnapshot vRanger"
The last command instructs our TUSSMYA SANmelody server to send a snapshot request to the AUSSMYB SANmelody server at the DR site in Austin following the transfer of the replicated backups.
USING THE REPLICATED BACKUPS
In the previous section we alluded to using snapshots at the DR facility. Snapshots allow us to make a usable coherency point on our AD-vRanger volume. This is advisable, because when our backups occur and the data is replicated to the DR site, the AD-vRanger volume will be changing as the replicated writes are "de-staged" into their corresponding locations.
In SANmelody, snapshots are a relationship between a "source" volume and a snapshot "destination" volume. SANmelody snapshots use "Copy On First Write" technology, and when based on Thin Provisioned volumes, the snapshots are not storage-costly.
A Snapshot Relationship for the Daily Backup
TURNING ON THE DR SITE
To use the replicated volume at the DR site, we map a snapshot of the "AD-vRanger" volume from our AUSSMYB SANmelody server to the DR site's Virtual Center / vRanger server.
We then discover the volume on the server with a "Rescan". Opening it, we find the vRanger PRO backup archives in tact, ready for use.
Mounted Snapshot of the Replicated Volume Ready For Use
RESTORING A REPLICATED VM
Although we have replicated our vRanger PRO archives, we've not replicated the vRanger PRO database which lists all the available archives. Obviously, the list of available archives will appear empty, as in the screenshot below. To restore our VM's, we will use the "Restore from Info" feature of vRanger PRO.
Restoring our VM's by Browsing For Info Files
Selecting "Restore From Info" produces a dialog with three screens. Our first step is to browse for our VM archives on the AD-Ranger snapshot volume. We select a differential backup of SQL01.
After selecting the VMs we wish to restore, we navigate to the second screen where we select the destination ESX host and associated VMFS datastore.
Navigating to the third screen, we accept the default options, and arbitrarily decide to rename the restored VM "DR-SQL01".
As you can see, vRanger PRO allows you to capture the commands for scripting the restoration process. If we are replicating a large number of VMs, this can facilitate bringing our DR site live.
Once the restore has completed, we successfully power on the VMs at the DR site. The ESX server will notice that the machine files have been moved and will recommend we create a new Unique Identifier (UUID). Selecting "Create", we dismiss the dialog.
The VM boots up. We're prepared... ready for a disaster.
Console of a Replicated VM at the DR Site
THE OFFSITE BACKUP
A business can spend a small fortune in backup services, transporting tapes offsite to a "secure" facility. Alas, if those tapes were hijacked en route and their contents have not been encrypted, the resulting situation can be as big a disaster as the one we're developing our DR site for. We might be better off using our replicated volumes to implement the offsite backups at our presumably secure DR site.
If the data connection between the two sites is secure, we won't have to worry about encryption. Nonetheless, as we have seen, vRanger PRO offers a data encryption feature.
Given the rash of recent incidents suffered by the large backup services companies and their customers, our vRanger / AIM internet highway solution clearly offers a more secure means of getting our backups offsite than using the traditional asphalt highway approach.
Once the vRanger backup files are at the DR site, we in effect have our "offsite backup". However, we have several options for what we do with those files. Clearly, we can present a snapshot of the replicated vRanger volume to our backup server and run a traditional backup to a tape library at the DR facilty. Additionally or alternatively we can simply use SANmelody's Complete Image Snapshot to make a clone of the snapshot onto a physically separate set of disks in effect, a disk-to-disk backup.
SANmelody and vRanger PRO products each offer powerful solutions for the datacenter. SANmelody is an outstanding software solution for implementing full-featured SANs and allows IT professionals to custom build their storage infrastructure according to their needs. vRanger PRO is the essential backup / restore tool for virtual server environments.
Bringing the two products together in an integrated DR / backup and offsite backup solution provides an elegant, reliable and cost effective means for businesses to protect their data and keep their applications available.