Snapshot 101: Copy-on-write vs Redirect-on-write

Good post by W. Curtis Preston (thank you)

There are two very different ways to create snapshots: copy-on-write and redirect-on-write. If IT is considering using the snapshot functionality of their storage system, it is essential to understand which type of snapshot it creates and the pros and cons of using either method.

Rather than the more common term volume, this column will use the term protected entity to refer to the entity being protected by a given snapshot. While it is true that the protected entity is typically a RAID volume, it is also true that some object storage systems do not use RAID. Their snapshots may be designed to protect other entities, including containers, a NAS share, etc. In this case, the protected entity may reside on a number of disk drives, but it does not reside on a volume in the RAID or LUN sense.

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More data services in VSAN 6.2

Good Post by Andrea Mauro (thank you)

As announced some months ago, the new Virtual SAN (VSAN 6.2) will add new data services making this solution more rich that before. Version 6.1 was announced during the last VMworld editions with some interesting features, including a ROBO scenario.

But was still limited in data service: better snapshot technologies, better VMFS, but still some limits and no deduplication, no compression, no erasure coding at all.

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Backup is not Archive

Good post by Joseph Ortiz (thank you)

In order to protect their data while dealing with explosive data growth, many organizations have started backing up their data to the cloud in an effort to reduce their storage and data center costs as well as obtaining data redundancy without the need to maintain a separate physical DR site. Many also mistakenly believe that these additional backup copies qualify as archive copies. Unfortunately, they do not.

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VVOLs and VMware

Post by Christine Taylor (thank you)

The definition of VVOLs is simple but the effect is ground-breaking. Here is the simple definition part: Virtual Volumes (VVOL) is an out-of-band communication protocol between array-based storage services and vSphere 6.

And here is the ground-breaking part: VVOLs enables a VM to communicate its data management requirements directly to the storage array. The idea is to automate and optimize storage resources at the VM level instead of placing data services at the LUN (block storage) or the file share (NAS) level.

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Is a Copy a Backup?

Good post by W.Curtis Preston (thank you)

Are we breaking backup in a new way by fixing it?  That’s the thought I had while interviewing Bryce Hein from Quantum. It made me think about a blog post I wrote four years ago asking whether or not snapshots and replication could be considered a backup.  The interview is an interesting one and the blog post has a lot of good points, along with quite a bit of banter in the comments section.
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How does Data Loss Happen and How can it be Stopped?

Good post by George Crump (thank you)

A recent blog by B&L Associates brought to light the problem of data loss. The entry cites surveys from Kroll Ontrack and EMC, which indicated that organizations see data loss as their single most significant risk and that the cost of losing data is almost two trillion dollars worldwide. Assuming that most of these organizations have some form of a data protection process in place and that those processes include some form of disaster recovery, why does data loss occur and how can it be prevented?

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Combining snapshots and backups for best practice data protection

Post by Simon Watkins (thank you)

When it comes to best practice data protection for your business-critical applications, no single snapshot or backup technology can provide the complete solution. Snapshots and backups have different yet complementary roles to play for availability, backup and disaster recovery.

When you’re looking for a comprehensive, tiered and converged data protection architecture that balances availability and protection, it should not be a question of either-or but more a case of where and how to best use snapshots and backup.  

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Virtual Volumes primer

Good post by Duncan Epping (thank you)

I was digging through my blog for a link to a virtual volumes primer article and I realized I never wrote one. I did an article which described what Virtual Volumes (VVol) is in 2012 but that is it. I am certain that Virtual Volumes is a feature that will be heavily used with vSphere 6.0 and beyond, so it was time to write a primer. What is Virtual Volumes about? What will they bring to the table?

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Orchestrating Copy Data

Post by George Crump (thank you)

2015 will be THE year of copy data management. Multiple vendors will bring solutions to the market. Many of these solutions will leverage snapshot technology in one form or another in an effort to reduce the capacity requirements of secondary data copies needed to drive data protection, business analytics, and test/dev operations. But there is another key resource that needs to be saved; time. Copy data solutions need to provide a high level of orchestration and analysis so that system administrators can be more efficient and decrease the chance for error.

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