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Linux Hot Copy Picks Up Where LVM Snapshot Leaves Off

Taking snapshots of applications is fast becoming a prerequisite for backup and recovery as well as a means for testing how well application fixes, patches and upgrades will work. But as more organizations adopt Linux as their preferred operating system to host their applications, they are also finding that the native Snapshot utility found in Linux’s Logical Volume Manager (LVM) does not provide them with all of the functionality they need.

It is for these reasons that more organizations are taking advantage of the freely available R1Soft Linux Hot Copy as it picks up where LVM snapshot leaves off.

As I talk to users and storage providers alike, three themes keep emerging in terms of why they need snapshot technology and what they hope to accomplish with it:

  • Backing up and recovering local applications in 30 minutes or less
  • Re-using snapshots for purposes such as testing fixes and upgrades as well as offsite recoveries
  • Managing snapshots as part of an organization’s broader data management and protection strategy

In this regard leveraging the native snapshot utility that is found in Linux LVM to deliver on these demands has been problematic at best. While the Linux LVM snapshot utility is “free”, it comes with some of the limitations that free utilities tend to possess. For example:

  • While LVM is widely available, it is not widely deployed
  • The snapshot feature only works on volumes where LVM is installed
  • The snapshot feature does not perform well when multiple snapshots need to be taken
  • There must be sufficient space on the LVM volume to support the snapshot’s creation and growth
  • Older versions of LVM may not support the creation of application snapshots since they do not first “freeze” the file system
  • Few if any third party data management products integrate with LVM so it cannot be easily brought under their management

It is for these reasons like these that more organizations are looking for a better snapshot utility to protect their Linux environments. It is for reasons like this that R1Soft is reporting a surge in interest in its freely available Linux Hot Copy snapshot utility from both end users and OEMs alike as Hot Copy for Linux differs from LVM snapshot in some key ways.
For instance, one problem that Linux Hot Copy addresses is the requirement to deploy LVM before snapshots can be created. One Linux administrator writes about his experiences when using LVM:

The good thing about LVM has been the ability to resize partitions as needed. It’s really been wonderful and once I discovered little magic trick of shrinking the file system below that of the partition, I haven’t had to worry about tromping on the end of my file system.

The really bad thing about LVM is that if you lose your root partition and you lose your LVM configuration files, you are so completely and totally screwed it’s not funny.  I’ve been in this position twice and only by sheer miracle have I been able to recover the LVM array.

R1Soft Linux Hot Copy does not need LVM in order to take snapshots so the root partition no longer has to reside on LVM in order to take snapshots of it. Further, Linux Hot Copy can create application consistent snapshots without the need to introduce a specialized file system such as the Veritas file system (VxFS).

Another differentiator is that LVM requires enough room on the volume so that it can create and store the snapshot. Further, if administrators are using LVM2 which supports Read/Write functionality, they may also need to keep additional space in reserve to make sure the snapshot has room to grow.

Linux Hot Copy differs in that it can use free space on existing file systems. This opens the door for administrators to create file systems and place snapshots on different, less expensive tiers of disk than what the production application may use. Now organizations can manage snapshot growth, present these snapshots to other servers for backup, recovery or testing and more cost-effectively scale out the storage capacity on which these snapshots reside.

A third Linux Hot Copy differentiator is that it removes the LVM number and maximum size limitations.  Using LVM snapshot, organizations generally can only create a single snapshot on the volume because additional snaps create so much overhead which precludes organizations from creating multiple online snapshots that they can use as recovery points. It also has a maximum capacity of about two TBs which may become an issue for organizations using LVM2 that are looking to read and write from the snapshot.

Linux Hot Copy eliminates these LVM snapshot limitations as Linux Hot Copy has no practical upper limit in terms of how large its read/write snapshot can grow. Further, Linux Hot Copy versions 3.3.0 or later are optimized for performance so organizations can create and retain multiple snapshots of the same device or volume so multiple recovery points can be created.

The final differentiator worth noting is that the flexibility of Linux Hot Copy allows it to be easily used and managed by other data management and protection applications. While R1Soft uses Linux Hot Copy in some of its other commercial software, storage providers are also starting to recognize the high-potential of the Linux tool. A prime example, Kubisys is starting to use the Linux Hot Copy technology in its Thin Capture appliance which enables organizations to non-disruptively make clones of their production applications in 15 minutes or less.

Soubir Acharya, Kubisys’s Founder and Director, says, “Linux Hot Copy works across a breadth of Linux systems, installs easily without requiring re-boots on almost all systems, has no prerequisites or setup required, and is easily integrated as part of a broader workflow.

Snapshot technology is becoming a must-have feature regardless of what application or operating systems organizations are looking to protect. However as Linux adoption accelerates in all size organizations, having a snapshot utility that can meet their needs and scale as they grow is becoming imperative.

R1Soft Linux Hot Copy is that Linux snapshot utility that can meet these new business needs. R1Soft’s decision to make it freely available gives organizations the freedom they need to immediately solve their pressing Linux backup and recovery or application testing requirements.

But because of Linux Hot Copy’s integration with other software, organizations can confidently deploy this solution into their Linux environment as they can look to other solutions from either R1Soft or its partners since it is a snapshot solution that can scale to meet whatever future backup, recovery and testing requirements that they may have.


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