NETGEAR is aware of a growing number of phone and online scams. To learn how to stay safe click here.
Forum Discussion
Solved
RAID Confusion on ReadNAS 628X
I currently have 5 of my 8 drive bays all filled with identical HDDs. They are configured in "X-RAID". I have two questions:
1. What is the difference, if any, between X-RAID and RAID 5?
2....
Hi XrayDoc88,
1. What is the difference, if any, between X-RAID and RAID 5?
X-RAID is the auto-expandable RAID technology that is available only on ReadyNAS systems. It uses the standard RAID levels, RAID 1, 5 and 6.
With two disks, it will use RAID-1. With three disks, it will use RAID-5. With 4 or more disks, you can optionally select X-RAID with dual redundancy(RAID-6).
With X-RAID, you can add storage space without reformatting the drives or moving the data from another location. You may check this link for more information about X-RAID.
2. I currently get 4 x my drive size as usuable storage space. If I add a sixth HDD, will I get 5 x my drive size as usuable space, or will the NAS automatically convert to RAID 6?
If the volume is configured with X-RAID with single redundancy (RAID-5), it will not automatically convert to RAID-6 when you add the 6th drive. Changing to X-RAID with dual redundancy (RAID-6) would require you to destroy and recreate the volume.
Regards,
One clarification - with RAID-5 the parity blocks are not stored on one disk. They are distributed evenly across all the disks. That improves write performance, and also balances the disk I/O evenly across all the disks.
Well I didn't know that fact. I also didn't know that in theory there is no maximum number of HDDs in a RAID 5 array. So with that understanding (just for fun) can the total usable space of a RAID 5 array truly always remain at total number of discs minus 1? It seems to me that if your number of discs got high enough, say 100, that the amount of distributed parity data must eventually equal more than a single disc size.
I don't know if there is a hard limit on raid-5, and if so it would probably vary depending on the particular implementation (ie linux may allow so many, while windows supported a different amount, plus there are hardware implementations (ie add in raid cards) which would have a hard physical number of drive it would support.
All that said, no one in their right mind would do 100+ disks in a raid 5 array, as the rebuild/sync time would be approaching infinite, and if you lost more than a single disk at the same time or during a rebuild/sync, you would loose all data across the whole set.
raid 6 doubles the redundancy so that if 2 disks fail you still have your data, but if a 3rd disk failed then again you would loose everything.
In the case of super large sets of disks, they would normally be in some kind of tiered approach, using multiple sets of disks in differing levels of raid, IE raid50 or raid60, where the parity stripes are constricted to specific sets of disks, resulting in increased redundancy (and accordingly less efficient total storage).
I think most would recommend a maximum of 24 disks in ANY array, but raid6 would be highly recommended for anything over 6 disks.
For example with sufficient disk slots, you could create different tiers with different performance and reliability, for example a 24 disk server:
- 4 disk raid 5 SSD perhaps for OS and apps
- 2 disk raid0 scratch disks for max performance temporary data
- 6 disk raid5 for high performance but with less redundancy (perhaps for stuff that gets modified and/or accessed frequently and/or by large number of clients)
- 12 disk raid 6 for regular performance with increased redundancy (perhaps for archive stuff that is stored and accessed less regularly)
obviously this is not designed for maximum storage, but for varied levels of performance spread across multiple disk sets and arrays.
finally, one should thoroughly understand that *NO* type of raid is a replacement for backups.
backups = multiple COPIES of your data, ideally on different physical devices, and even multiple locations.
consider not only disk/hardware/software failure, but also user error, virus/malware, malicious users, fire/flood/acts of nature, and physical theft.
Thanks TeknoJnky. My future goal is to back up my ReadyNAS in total as you describe. Currently I have specific folders backed up on various external hard drives located in my house. It is a clunky, manual system. I don't truly trust cloud storage or mainly don't want to spend the money. But as my NAS grows, it almost becomes necessary to build another NAS just to use as the backup. That gets expensive. I currently have about 11 TB of data on my NAS. I guess I could compare the cost of perpetual cloud backup to the cost of building the 2nd NAS. :)
Yes, as storage requirements go up, so does the expense.
Welcome to the club. :)
As you mention, upgrading to or building a new nas, then using the old nas as a backup is a fairly common solution.
And after several years of upgrades, you might find yourself with a good selection of devices which can be used to continously back each other up.
I myself have 4 active readynas devices, my main nas which is then backed up in sections to the others.
Over time, as I upgrade to larger hard drives, I reuse them to upgrade the older nas's as well.
XrayDoc88 wrote:
Currently I have specific folders backed up on various external hard drives located in my house. It is a clunky, manual system. I don't truly trust cloud storage or mainly don't want to spend the money. But as my NAS grows, it almost becomes necessary to build another NAS just to use as the backup. That gets expensive. I currently have about 11 TB of data on my NAS. I guess I could compare the cost of perpetual cloud backup to the cost of building the 2nd NAS. :)
We have similar amounts of data.
I use Crashplan Pro for disaster recovery - protecting against theft, fire, flood, ransomware, etc. The cost is $10 per month for a single computer (e.g. the NAS) - which I think is reasonable. But if the restore speed matches the backup speed, then it would take several months to restore all the data. So there is still a need for local backup (even if you choose to fully trust the cloud provider).
I do use other NAS for local backup - although I agree it is more expensive than external drives. If you were starting from scratch, an RN212 + two 8 TB drives (jbod) would cost about $600, while two 8 TB external disks would cost about $300. So the incremental cost of using a second NAS could be as low as $300.
A "in between" approach is to get a two or four bay SATA enclosure for backup, and connect that to a PC. You can set up scripts (or use free tools) to wake up the PC on schedule and do incremental backups of the NAS.
NETGEAR Academy
Boost your skills with the Netgear Academy - Get trained, certified and stay ahead with the latest Netgear technology!
Join Us!
