Resources for IT Professionals. Sign in. United States English. Ask a question. Quick access. Search related threads. Remove From My Forums. How many drives can fail in a RAID configuration? Recent Topics Archive. Subscribe to Updates. All Rights Reserved. RAID 5 results in the loss of storage capacity equivalent to the capacity of one hard drive from the volume. For example, three GB hard drives added together comprise GB or roughly about 1. If these same three 3 drives are configured as a RAID 5 volume striped with parity , the usable data storage capacity would be GB and not GB, since GB the equivalent of one drives' capacity would be utilized for parity.
In addition, if two 2 or more drives fail or become corrupted at the same time, all data on the volume would be inaccessible to the user. A: Many times information is still recoverable, depending on how the drives were re-formatted. Re-formatting a volume using Windows, for example, will create what will appear to be a new "clean" volume - but the original data will still be on the disk in the "free and available" space.
However, a low-level format usually performed through an on-board RAID controller utility will "wipe" or overwrite every single block on a drive. A: The safest approach to data recovery with a RAID volume or with any media is to capture every storage block on each device individually.
The resulting drive "images" are then used to help rebuild the original array structure and recover the necessary files and folders. If we have 4 disk and configured raid It will do stripping means fast data flow as data being distributed but what is pairity for?
The parity is used for recovering data in case of drive failure. With RAID6 two disks can die simultaneously. More detailed descriptions of the way parity works can be found elsewhere on the web. This page is meant to give a general overview. Having an extra offsite disk is a good idea. In many NAS enclosures it is a bit of a hassle to swap drives. Once something is clunky, you stop doing it after a while.
Why not use a separate harddisk docking station for the off-site copy? I am looking to install an external multiple bay NAS drive for home use. Approximately TB, keeping in mind performance and that I will be backing up all data on an external HDD stored in my safe.
What would be the best RAID configuration to use? Thank You for any insight and information. What an excellent explanation of RAID….. Thank you so much. Hi, I have read your explanations about RAID configuration and it is very much informative with pictures. If I understand your first question correctly, you are wondering if you can use a smaller drive for parity compared to the other drives in the RAID set.
The hardware or software RAID controller determines if you can mix different sizes and types of drives. Many require all drives to have the same capacity.
Alternatively they use the capacity of the smallest drive across all of them. Please note that it is 6 gigabit per second, not 6 gigabyte per second. There is some overhead which means the fastest real transfer speed is around megabyte per second. A hard disk cannot reach that maximum speed, only SSDs are capable of doing that. You should also keep in mind that if you copy files from one logical drive to another on the same HDD, your computer is reading from and writing to the same drive simultaneously.
That also slows down the data transfer. To take advantage of Sata 3 speeds, you need both a Sata 3 drive and a Sata 3 controller. Also as noted, the 6 gigabit-per-second transfer rate specified for Sata 3 is only what the controller is capable of. A Sata 3 hard disk will never achieve a full 6Gb per second transfer rate, but it will be way faster than a Sata 2 drive.
SSDs will get you much closer than any hard drive, but no storage media will actually ever reach the maximum transfer rate of the controller. The type of data being transferred is a significant factor in this as well. Also the 6Gb per second Sata 3 transfer rate only applies to sequential reads, which are faster than random reads, particularly on rotating media.
Write operations are much slower, as the media itself is the bottleneck. Can you please tell me what is the maximum size for one virtual disk under RAID 1. What is the largest disk size it supports? I have a Gb and a gb drives If i RAID 0 with them will I get gb of space under one drive or will it be limit to gb being to lowest size of the two? The storage space added to the array by each disk is limited to the size of the smallest one, which means this would be very unefficient.
If your smallest drive is GB, then a raid 0 configuration would give you twice that amount, or GB. You can certainly do this. I would just get a second large disk though. HDDs are moving back to being cheap again. Set aside the smaller disk for a backup drive and sync some important folders to it.
The other disadvantage is that you cannot go back in time and recover a file you accidentally deleted two days ago.
Previous Versions. I personally have two external disk enclosures and alternate back-ups of all data on these enclosures.
One of them is stored at my parents house and during each visit I swap them out so I always have an off-site backup. There are two disadvantages of just mirroring your data on additional internal disks: your backup is physically in the same location so if the PC gets stolen or there is a fire everything is gone.
If you attach a separate box containing two or more drives to a computer and those drives are running in a RAID configuration, there is a circuit board in that box that handles the distribution of the data across the drives. That board has its own CPU: it is effectively a mini computer but it typically is called a hardware controller. Most of it is in an alternate location 3tb and that is also spent so another external drive without a backup is being used.
I am wondering if a mirrored 12 or 16 gb raid 1 drive is a good idea my current 4tb can be moved to the other locale giving me 7tb. I anticipate using at least 1TB in the next year and possibly more. If I understand it correctly you currently have around 6 TB of data and you expect to add at least 1 TB each year. I am not familiar with the brands you mention. Have a look at Drobo as well — their RAID boxes seem to be pretty popular but there are dozens of alternatives on the market.
I would stay away from RAID with such a setup. RAID works best for drives with the same capacity and using the same type of controller. If you want higher throughput remove the big drives from their external enclosure and put them internally on SATA 6. That is faster than most USB3 controllers. Is it possible you can explain to me how to do the following or direct me to a tutorial?
On the other hand, I have lost many hard drives and all the information from crashes. Mounting drives on Windows 7 is explained on this Microsoft page. I cannot give you a short and relevant description of how to do this, especially not without any knowledge of your setup.
Once that is done, the RAID volume can be partionned and formatted from within the operating system. That depends on your definition of important. For company servers, RAID 6 is probably the way to go right now. Hi, just want to check if i understand.
So for example.. A storage box consists of an array of 6 disks, 1 TB each and the effective storage capacity, based on the RAID level used is. The way you have explained using simple terms I really liked it. But what I feel is you should have included RAID 6 as it can withstand failure of more than one disk. Its interesting to learn something that is quite different from that of others.
There are lots of heated discussions about that on the web. If you run benchmark software to measure the performance of striped SSD drives, there is a significant speed increase. Wikipedia is clearer! Fixed — Fine nuances like that are difficult to grasp for me since English is not my native language. Normal procedure is to use raid4 to resync and then revert back to raid0. From everything I am seeing on comparisons between both, if you only have 4 disks, the fault tolerance and performance are the same.
My guess based on my mathematical intuition is that if you have a number of drives that is a power of 2 it will be the same. I need to deal with very large data set with typical file size of gb, hundreds of them, in a workstation. Both read and write. Would Raid 3 be better than Raid10? Raid 5 only requires a minimum of 3 disks. As for file size, that is upto whatever file system you put on the volume created by you Raid array.
I have used RAID 6 in one of my server. This has allowed me to create two hot swap disks. I deceided to use it on case scenarios such as: if two active disks fail at the same time. Featured in a NEC server rack mount. I have head that the government is now doing work on RAID yes, negative This technology is based on tensors and promises to put all other RAID to shame. I am a newbie when it comes to NAS. I am trying to configure 4 drives of 3 TB each. That means your effective capacity will be 6 TB.
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