Redundant array of independent/inexpensive disks; a technology which utilizes multiple disks to provide increased reliability, performance, and/or redundancy. Can be implemented either in software or with a hardware controller.

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30
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7answers
67k views

How can I make mdadm auto-assemble RAID after each boot?

I successfully created a RAID (mirroring) by utilizing mdadm. However, I must run the following commands after each boot: mdadm --stop --scan // to stop /dev/md127 - I don't know where the number 127 ...
24
votes
12answers
3k views

What are my options for a multi-Terabyte home NAS? [closed]

I've got alot of DVDs and have been slowly ripping, encoding, and tagging them and I've nearly filled my WD MyBook 1TB. I'm estimating that I've got about 1.5 or 2Tb to go to complete my current ...
24
votes
5answers
50k views

Which software raid modes does each version of Windows 7 support?

Being familiar with the software raid modes and dynamic disks from the server versions, I was wondering if there is a document or even just common crowd knowledge that indicated what software raid ...
23
votes
3answers
2k views

Detecting when a server is running on UPS battery

I have a home server (HP Proliant ML310 G4) that I bought from my employer a month or so ago. The server runs Debian Linux and I use it for just about everything. I can get away with doing this ...
23
votes
8answers
121k views

How to get an inactive RAID device working again?

After booting, my RAID1 device (/dev/md_d0 *) sometimes goes in some funny state and I cannot mount it. * Originally I created /dev/md0 but it has somehow changed itself into /dev/md_d0. # mount /...
22
votes
3answers
17k views

Intel Matrix Storage Manager vs Linux Software RAID

The chipset I'm using supports the Intel RSTe technology. It means that I have two options for RAID setup: Ordinary linux software RAID, using mdadm command. RSTe (either by the BIOS or, again, ...
20
votes
9answers
35k views

Simple mdadm RAID 1 not activating spare

I had created two 2TB HDD partitions (/dev/sdb1 and /dev/sdc1) in a RAID 1 array called /dev/md0 using mdadm on Ubuntu 12.04 LTS Precise Pangolin. The command sudo mdadm --detail /dev/md0 used to ...
18
votes
5answers
36k views

How does parity work on a RAID-5 array?

I'm looking to build a nice little RAID array for dedicated backups. I'd like to have about 2-4TB of space available, as I have this nasty little habit of digitizing everything. Thus, I need a lot of ...
17
votes
2answers
43k views

Can I set up a RAID 5 with a bunch of drives of different sizes?

I currently have 3 1TB drives, a couple 500GB ones and some 750GB ones. Can I put them all in a RAID 5 configuration or do they need to be of same size?
17
votes
9answers
18k views

RAID 0 performance gains?

I'm building a new computer over the summer. I'm fairly competent in computer hardware, and am thus building the computer from scratch. I have everything planned out, but I was wondering about RAID. ...
17
votes
3answers
15k views

Does software RAID 1 in Windows 7 improve read speeds?

Does software RAID 1 (mirroring) in Windows 7 improve read speeds? I'd like to set up RAID 1 to help protect my important documents (yes, yes, I know it's not a backup), but performance is also ...
14
votes
7answers
18k views

Onboard RAID vs Software RAID

My motherboard, an Asus M4a79t Deluxe, advertises RAID 0/1/5 capabilities. My limited understanding is that onboard RAID is better than software RAID. Is this necessarily true? Is an onboard RAID ...
14
votes
10answers
8k views

Looking for an actual experience of RAID 5 2 drive failure? [closed]

I'm wondering if anyone has any personal experience of RAID 5 2 drive failure with large drives? As I understand it, the theory is that with large 1-2TB drives, if one drive fails in the raid set, it ...
14
votes
4answers
9k views

Does fake RAID offer any advantage over software RAID?

Does a fake RAID controller do any useful work or is it just like a place where to store the parameters? I know that Linux offers much more flexibility than my poor on-board controller, but this is ...
14
votes
5answers
38k views

Can a mirrored (RAID-1) disk be plugged into another system to be read?

If I have disks in a RAID-1 array, can I take one of them out and plug it into a different system to be read? This means, on the target system, treating the disk from the RAID array just like an ...
14
votes
2answers
11k views

Can I setup a software RAID in Windows 7 using Virtual Hard Disks?

Well, the title of my question pretty much sums it up, but let me elaborate. The main idea of what I want to do is as follows: 1) I have two separate hard disks, with nearly equal performance. I use ...
13
votes
5answers
3k views

Is TRIM supported on RAID 0 configurations for SSD drives in Windows 7?

I know this question has probably been asked at some point in the past, but I am trying to figure out if Windows 7 supports passing TRIM commands through RAID controllers yet. I am trying to decide ...
13
votes
5answers
3k views

Alternatives to Windows Home Server Drive Extender?

As Microsoft is cutting support for Drive Extender in Windows Home Server v2 (Windows Server Codename Vail is the official name), what are the alternatives to Drive Extender on a self-built machine? ...
13
votes
1answer
11k views

How do I check Windows 7 Software RAID Rebuild Progress from the Command Line?

I use software RAID on my Windows 7 ultimate box media center. Unfortunately, Windows decides it needs to rebuild my software RAID pair much more often than I'd like. The most common way to see the ...
12
votes
8answers
8k views

What RAID configuration is most appropriate for a home user?

I have a computer for general home use and mild gaming (not upgraded the graphics card so still on AGPx8). It is currently configured for striped access over two 80GB disks. Is this the best option? ...
12
votes
10answers
57k views

What's the difference between RAID 1 software mirroring and Fake RAID?

I've just ordered two new hard drives for my main desktop and a copy of Windows 7 Professional 64-bit. I'd like to do a clean install of Windows 7 onto the new drives (leaving my old Windows XP ...
12
votes
3answers
30k views

How-to change the name of an MD device (mdadm)

Here is the output from mdadm -Esv: ARRAY /dev/md127 level=raid0 num-devices=2 UUID=d89d9d45:9a420812:c44c77eb:7ee19756 devices=/dev/sdb8,/dev/sda8 This is a v0.90 array. The question is as ...
12
votes
4answers
1k views

Is it worth buying SSDs for a RAID?

Im seeing people using SSDs for RAID-0 and getting excellent improvements in read/write rates. But now there is a good opportunity to acquire another SSD Force Corsair F60 identical to mine. I'm ...
12
votes
2answers
4k views

Can a failed Btrfs drive in RAID-1 be replaced live?

I am trying to decide on a filesystem and would like to know if it is possible to replace a failed drive in btrfs RAID without downtime. Suppose I create a new btrfs filesystem using the command ...
11
votes
5answers
25k views

ZFS Beginner Setup with Different Size Drives

Sorry for the noobie questions, I've been Googling all sorts of walkthroughs to create my ZFS raid, but I can't seem to find the correct links for the answers I'm looking for. This is my first ...
11
votes
2answers
4k views

Formula to calculate probability of unrecoverable read error during RAID rebuild

I want to compare the reliability of different RAID systems with either consumer (URE/bit = 1e-14) or enterprise (URE/bit = 1e-15) drives. The formula to have the probability of success of a rebuild (...
10
votes
2answers
7k views

Is there a RAID 7?

One of my friends at school was talking about a RAID, he said there was a RAID 7, as to my knowledge no such thing exists. Could someone clarify? I don't think there is but just making sure.
10
votes
1answer
528 views

Where is the software RAID information actually written?

Like title says, where is the actual information which specifies which disks are being used, what order, etc...? I noticed while installing a linux distro that it was detecting a RAID array without a ...
9
votes
4answers
10k views

Does RAID1 increase performance with Linux mdadm?

I have a cheap 2-bay NAS with a 2TB HDD. To be robust against disk failure, I'm thinking of buying a second 2TB HDD and putting it in RAID1 with Linux mdadm. The file system is ext4. Will this ...
9
votes
4answers
14k views

Start a ZFS RAIDZ zpool with two discs then add a third?

Let's say I have two 2TB HDDs and I want to start my first ZFS zpool. Is it possible to create a RAIDZ with just those two discs, giving me 2TB of usable storage (if I understand it right) and then ...
9
votes
3answers
3k views

Any difference between Hardware RAID and Software RAID?

I'm building a new server (Small Business Server 2008), but I can't get the built-in RAID controller (AMD SB700) to work and have basically given up on it ever working with Server 2008. Fine. But my ...
9
votes
5answers
6k views

should I put my multi-device btrfs filesystem on disk partitions or raw devices?

If I'm going to create a multi-device btrfs filesystem. The official recommendation from the documentation apppears to be to create it on raw devices; i.e. /dev/sdb, /dev/sdc, etc, but this is not ...
9
votes
1answer
7k views

Is it possible to create a software RAID 1 with different sector sizes?

I bought a hard drive of a different model to my main drive and tried to mirrored them, but the following error message came up in Windows 7 Virtual Disk Manager: All disks holding extends for a ...
9
votes
2answers
2k views

New SSD (Corsair) takes 1-2 minutes before it's found after first boot

My new SSD Corsair CSSD-F60 actually works - using it for boot and system disk (Windows 7 64-bit). But when first (cold-) booting the PC it's not properly found by BIOS and Intel ICH9R Controller. The ...
8
votes
12answers
8k views

Is RAID 0 as risky as people say it is?

I'm just about to set up my hard drives with RAID 0. Is it really as risky as people say it is?
8
votes
2answers
3k views

Is a home NAS reliable to keep your data on (no other backups)?

The question came up while I was thinking to move some data (e.g.) pictures, old but important other data solely to the NAS (private use, no business level). My NAS is a simple 2 disk RAID system. I ...
8
votes
3answers
13k views

Matched or unmatched drives for RAID arrays?

Looking around there is conflciting information on this, with some strongly suggesting one or the other. From my understanding the issue with matched drives is that the wear on both drives is more or ...
8
votes
3answers
3k views

optimal SATA SSD configuration in new PC

I'm sold on SATA SSDs for my next PC but since their prices grow un-proportionally to their size, I'm wondering what would be the best configuration for them (for OS and Programs) would be: 2 SSDs ...
8
votes
2answers
9k views

Software RAID Windows 10

I have always had a hardware RAID 5, but recently lost tons of data due to a drive loss, even after recovery steps. I am trying to set up a RAID 1 on 3 drives, and I do not see the option "Add ...
8
votes
3answers
6k views

What advantages and disadvantages have Hybrid SSD/HDD RAIDs

I just read about Hybrid RAID arrays consisting of SSDs and common HDDs which are supported by Adaptec's RAID controllers. Does such a RAID configuration provide real advantage? Isn't write ...
8
votes
1answer
7k views

Shrink RAID by removing a disk?

I have a Synology NAS with 12 bays. Initially, we decided to allocate all 12 disks for a single RAID-6 volume, but now we would like to shrink the volume to use only 10 disks and assign two HDDs as ...
8
votes
2answers
8k views

Solid State Drive Occasionally Freezes For A Minute While OS Is “Beach Balling”

Almost a month ago I bought Intel 330 128GB solid state drive, migrated my data with Intel branded limited-feature Acronis from old HDD to new SSD, optimized with Intel Toolbox and started using it. ...
8
votes
4answers
3k views

How long does data stay in a RAID cache?

Most higher-end RAID cards have the option to purchase a battery add-on to allow the controller to finish writing the contents of the cache to the drives in the event of a power failure. I setup ...
8
votes
5answers
2k views

Looking for tips: building a workstation around Xen and GPU pass-through

I'm building my new home machine right now and as usual this will be a heavily overloaded workstation that will serve as development and testing machine, file server and game console (plus I'm adding ...
8
votes
3answers
5k views

Raid1 with active and spare partition

I am having the following problem with a RAID1 software raid partition on my Ubuntu system (10.04 LTS, 2.6.32-24-server in case it matters). One of my disks (sdb5) reported I/O errors and was ...
7
votes
10answers
11k views

Use RAID for desktop computer?

I'm building a new computer over the summer. I'm fairly competent in computer hardware, and am thus building the computer from scratch. I have everything planned out, but I was wondering if I should ...
7
votes
7answers
26k views

Should I use “Raid 5 + spare” or “Raid 6”?

What is "Raid 5 + Spare" (excerpt from User Manual, Sect 4.17.2, P.54): RAID5+Spare: RAID 5+Spare is a RAID 5 array in which one disk is used as spare to rebuild the system as soon as a disk fails (...
7
votes
5answers
3k views

Are there any USB flash drives or SD cards which use RAID or redundant storage for additional reliability?

I'm looking to get a fault-tolerant USB flash drive, which saves data to multiple independent locations, whether using RAID or some other means to back up data. Has a product like this ever been ...
7
votes
3answers
3k views

Will mirroring with an SSD improve read performance?

If you use Windows 7 to mirror a volume across an SSD drive and a mechanical hard drive, will the read performance be similar to a single SSD drive? I.e. is Windows smart enough to read from them ...
7
votes
3answers
3k views

To RAID or not to RAID: SSDs and virtualization

I am approaching that time where my main PC has slowed enough due to Windows rot that I should probably reinstall. Instead of spending a week arm-wrestling, reinstalling and configuring only to find ...