RAID stands for Redundant Array of Independent Disks, and is a technology which can provide increased reliability, performance, and/or redundancy by utilizing multiple hard drives simultaneously. RAID can be implemented in a computer via either a hardware or software controller.

learn more… | top users | synonyms

25
votes
5answers
52k 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 ...
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
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 ...
23
votes
5answers
48k 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 ...
20
votes
8answers
100k 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 ...
18
votes
9answers
29k 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 ...
17
votes
1answer
13k 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, ...
16
votes
5answers
28k 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 ...
16
votes
9answers
17k 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. ...
15
votes
2answers
13k 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
14k 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 ...
13
votes
10answers
7k 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 ...
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
2answers
32k 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?
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
2answers
9k 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 ...
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
1answer
9k 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 ...
11
votes
4answers
7k 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 ...
11
votes
7answers
6k 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? ...
11
votes
11answers
56k 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 ...
11
votes
3answers
24k 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 ...
11
votes
2answers
3k 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
6k 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
519 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 ...
10
votes
2answers
3k 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 ...
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
28k 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 ...
9
votes
1answer
6k 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
1k 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
6k 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
4answers
7k 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 ...
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
5answers
4k 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 ...
8
votes
2answers
7k 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
2k 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 ...
7
votes
10answers
10k 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
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
4answers
16k 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 ...
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 ...
7
votes
1answer
210 views

SATA III 6Gb/s, is that 6gbit/sec per device, or for the entire controller?

If I have (12) SSD drives in a RAID6, will the max connection speed of each drive be 6Gbps, or is that for the entire controller?
7
votes
2answers
927 views

Is the speed difference I get from putting my SSD in RAID mode negligible?

I've got two 80GB Gen2 Intel SSDs, currently in RAID 0. I'm about to reformat for an unrelated reason, and I'm wondering if maybe I should just leave them as independent drives. The primary reason ...
7
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 ...
7
votes
4answers
656 views

One of two RAID 1s is not recognized in Ubuntu 13.04

I have a 256GB SSD (Ubuntu/Win8), and two 1TB drives in RAID 1. The problem is that I just recently added another two drives that are 4TB in RAID 1 but they aren't detected in Ubuntu as one drive but ...
7
votes
2answers
2k views

Make two disks appear as one big share on LAN

I bought 2 x 2TB disks for a NAS server, (linux debian). I want to make both drives appear as one big 4TB disk on the LAN. This can be done with software RAID (JBOD) or LVM I suppose. There are other ...
7
votes
3answers
4k 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 ...
6
votes
2answers
2k 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 ...
6
votes
4answers
4k views

RAID 1 on 2 external HDDs

I have an Ubuntu 12.04 server on my old laptop. Its HDD (160 GB) is too small for the file storage I need, so I'd like to attach a couple of external HDDs to it (through USB ports). The data I'll keep ...