Network Storage Tips


NAS RAID For Network Storage Data Protection

NAS RAID is technology used in the network attached storage devices we review and compare here at Network Storage Tips.

The acronym stands for Redundant Array of Independent Disks, and has many advantage when properly configured in a NAS device.

The benefits of NAS RAID include:

  • Prevent data loss due to hard drive failure
  • Provide faster access to larger volumes
  • Allow dynamic data volume expansion without backup & restore

One method of using RAID hard drives is to use RAID level 0, which is a method of joining hard drives together to increase the size of a data volume and provide the fastest access to the data. It does NOT, however, protect your data in the event of a hard drive failure UNLESS teamed with RAID mirroring as in RAID 0+1.

nas-raid-1-illustrationFor purposes of discussion, that being network storage tips, RAID 0 is not very practical and, along with JBOD, is not recommended for home network storage for sure, and only very infrequently for SMB or enterprise network storage needs.

RAID 1 is the most basic RAID level that protects your data, unfortunately it is the most expensive per megabyte of data storage usable. For every hard drive in a RAID hard drive array, there is an identical or larger drive “mirroring” that original.

When either drive fails in a RAID 1 array, the other drive continues to store and allow access to the data.

RAID 1 uses even numbers of hard drives then, naturally, although if more than two hard drives are in a NAS device then RAID 5 is more typically the level of protection chosen.

RAID 0+1 is sometimes shown as a capability of a network attached storage device but the situations where that is warranted are rare.

NAS RAID 1 is the only redundant hard drive data protection available for two hard drive home network storage devices.

nas-raid-5-illustrationRAID 5 is the other most common RAID hard drive arrangement found on the NAS devices reviewed here at Network Storage Tips. RAID 5 requires at least 3 hard drives, but more can be added. RAID 5 is more efficient in that only 1 “wasted” drive needs to be purchased to provide the RAID array protection.

If any drive fails in a RAID 5 array, the system can rebuild the data once that drive is replaced based on information stored on the other drives.

RAID 5 will typically be the minimum protection employed in a moderately sized small to medium business NAS device.

With the newer RAID 6 protection, a NAS RAID device can actually sustain two hard drive failures without incurring data loss.

This is a benefit over RAID 5 with hot spare due to today’s larger data volumes requiring long synchronization times that leaves a RAID 5 with hot spare volume vulnerable to a second drive failure during the time required for the rebuild onto the hot spare.

The better protection against data loss and downtime is becoming quite common in 6 drive and larger enterprise network storage devices.

The key to data loss prevention

Whether your network attached storage device is protected with RAID 1, RAID 5 or even RAID6, the key to data loss prevention is to replace the failed drive as soon as possible so that subsequent failures do not result in data loss due to the reduced level of NAS RAID protection.

I have seen servers with RAID data arrays in past years run for an extended period of time in a degraded state (with a failed drive) because there was no one checking that status of the RAID protection to know that a drive had failed. Once the next hard drive fails, data is lost, down time and significant expense is incurred and can even cause business failure.

With my consulting clients I implemented a maintenance program whereby a technician checked RAID status weekly on Windows servers – but there is even risk in that!

The NAS devices reviewed on this website typically have the ability to configure an email alert and even an indicator light on the front of the device to notify the responsible person that a drive has failed, or in some cases, predicted to fail utilizing the drive’s own S.M.A.R.T. status.

Hard drives can and occasionally do fail within close time proximity to each other. That makes RAID 6 with all available alert mechanisms employed highly desireable to insure that a failed drive is promptly replaced and data is not put to undue risk.

Always make sure that any email alerts are properly configured to a valid email account that is monitored and that the email will not be diverted to a SPAM folder.

Recommended NAS RAID Devices

We really like the Netgear ReadyNAS lineup of NAS RAID devices due to the patented X-RAID and X-RAID2 technology which improves upon basic RAID array benefits and the ability to easily monitor for failed or pending failed RAID array disks.

X-RAID and X-RAID2 still implement a standard RAID 1, RAID 5 or RAID 6 data protection scheme “under the hood”.

Most notably, X-RAID2 allows for volume expansion without downtime or a backup, wipeout, restore process (which can be somewhat stressful in addition to the inconvenience of the downtime). Even a power outage during the expansion process will not result in a loss of data – but make sure your backups are up to date just to be sure!


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