RAID solution handled by the operating system.

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46
votes
10answers
7k views

RAID - software vs. hardware

I have always used hardware based RAID because it (IMHO) is on the right level (feel free to dispute this), and because OS failures are more common to me than hardware issues. Thus if the OS fails the ...
31
votes
7answers
53k views

How to interrupt software raid resync?

I want to interrupt a running resync operation on a debian squeeze software raid. (This is the regular scheduled compare resync. The raid array is still clean in such a case. Do not confuse this with ...
29
votes
2answers
28k views

How do I tell if grub is installed on a device?

How can I tell if grub is installed on a disk, and if it is what settings it has (noteably, what it has for the root parameter) I need to check a lot of disks in software RAID1 arrays to make sure ...
23
votes
5answers
13k views

What is better LVM on RAID or RAID on LVM?

I currently have LVM on software RAID, but I'd like to ask you what you think it is better solution, maybe some pros and cons? Edit: It is about software raid on lvm or lvm on software raid. I know ...
22
votes
2answers
9k views

Readahead Settings for LVM, Device-Mapper, Software Raid and Block Devices - what wins?

I've been trying to find a straight answer on this one, and it has proved elusive. This question and its answer is close, but does not really give me the specifics I would like. Let's start with ...
19
votes
2answers
646 views

Sanity check on 40TB server configuration

I've got 40 years in computing, but I've never had to build a server quite like this one, so this might be a n00b question. I have a client that is going to offer ultra-high def music files for ...
18
votes
3answers
9k views

Can you change the metadata version on an existing array?

So grub requires metadata version 0.90 I'm wondering if I can change my existing arrays to use that instead of the default which is 1.2. That way I don't have to go about a reinstall. If yes, how can ...
14
votes
5answers
12k views

Best way to grow Linux software RAID 1 to RAID 10

mdadm does not seem to support growing an array from level 1 to level 10. I have two disks in RAID 1. I want to add two new disks and convert the array to a four disk RAID 10 array. My current ...
13
votes
6answers
53k views

How to view status of software RAID 1 resynching?

I have two 500 GB disks and yesterday I mirrored first drive to the second one using software RAID 1. PC has now been on for 30 hours. Both disks say "Resynching", but there is no progress indicator. ...
12
votes
11answers
2k views

Is RAID5 more robust than RAID1

I am about to replace an old hardware RAID5 array with a Linux software RAID1 array. I was talking to a friend and he claimed that RAID5 was more robust than RAID1. His claim was that with RAID5, on ...
11
votes
2answers
16k views

How do I move a Linux software RAID to a new machine?

I have a newly built machine with a fresh Gentoo Linux install and a software RAID 5 array from another machine (4 IDE disks connected to off-board PCI controllers). I've successfully moved the ...
10
votes
2answers
2k views

Linux mdadm software RAID 6 - does it support bit corruption recovery?

Wikipedia says "RAID 2 is the only standard RAID level, other than some implementations of RAID 6, which can automatically recover accurate data from single-bit corruption in data." Does anyone know ...
10
votes
3answers
7k views

Deciphering continuing mpt2sas syslog messages

Summary I have been getting these cryptic messages in syslog since I installed some new hardware and I can't figure out what the problem is, if it's serious, or what to do about it. They're from the ...
10
votes
5answers
12k views

How do you monitor the health of a mirrored disk in Windows?

I have a Mirrored Dynamic disk on my Windows 2003 Server. How do you monitor the health of the volume? Is there a way to have the server send an email when there is an issue with the volume? Is there ...
10
votes
3answers
6k views

LVM volume group shared between KVM/libvirt host and guests: is this a bad idea?

I have just built a shiny new KVM/libvirt-based virtual machine host, containing 4 SATA II hard drives, and running CentOS 5.5 x86_64. I have decided to create virtual machine disks as logical ...
10
votes
1answer
7k views

Easy to expand Linux software RAID 5 with XFS. Best practices?

I use my Ubuntu machine as a file server for Windows/Linux/Mac clients using a Samba share. I need it to be easily expandable by just adding more hard drives without having to move any data back and ...
9
votes
1answer
5k views

Implementing Linux fstrim on SSD with software md-raid

I'm currently building a new Ubuntu 13.04 server with 2 256GB SSDs in a raid mirror to run a MariaDB instance. We typically place LVM on top of dm-crypt encryption on top of an md raid 1 array, but ...
9
votes
5answers
4k views

Boot Debian while RAID array is degraded

Recently, I came across Ubuntu Server install. During install, it asked me whether or not to allow booting system from degraded RAID array (probably because I installed system onto RAID1 /dev/md0 ...
8
votes
1answer
15k views

KVM guest io is much slower than host io: is that normal?

I have a Qemu-KVM host system setup on CentOS 6.3. Four 1TB SATA HDDs working in Software RAID10. Guest CentOS 6.3 is installed on separate LVM. People say that they see guest performance almost equal ...
8
votes
5answers
5k views

Software vs. Hardware RAID1 (Mirror)

How does the Software Mirror in Windows Server systems compare to an affordable hardware/BIOS RAID? I've had some rather bad experiences with onboard hardware RAID controllers, so I would want to ...
8
votes
2answers
3k views

Convert linux software raid from raid5 to raid6

I currently have a file server with 3 1.5TB disks in a RAID5 array. Since it's pretty much full, I got three additional disks (also 1.5TB each). Now I'd like to switch to RAID6 since 6TB space is ...
8
votes
2answers
983 views

How to attach an existing RAID1 to a fresh Linux system?

I have a RAID1 currently operating on a single hard drive (yes, the mirror is absent). Is it possible to reorganize my system using the following algorithm? I set up another single-disk RAID1 (onto ...
8
votes
1answer
2k views

Can I use dmraid instead of md (mdadm) to make software RAID-1 and RAID-1+0 volumes?

On a related question about SSDs and TRIM (see: Possible to get SSD TRIM (discard) working on ext4 + LVM + software RAID in Linux? ), it turns out that dmraid may now (or shortly) support TRIM on ...
8
votes
2answers
1k views

Linux Software Raid 10 hung after 1 drive failed, mdadm will not let me force remove the faulty device

I have a Linux software raid 10 setup consisting of 5 RAID 1s (Two drives per mirrored setup) and a RAID 0 across all 5 RAID 1 pairs. To test that none of the drives were going to fail quickly under ...
7
votes
3answers
863 views

Do disks in Raid-1 function outside of the raid?

Raid-1 is mirroring two disks (if I haven't messed up completely here :p). Does that mean that I could take one disk out and put it into another machine and it would work like a normal disk? Or does ...
7
votes
2answers
399 views

Are different RAID cards setups compatible?

I'm setting up a new NAS/SAN system with RAID5, and I was wondering if going the software or hardware RAID way because I had this question in mind: If my hardware-RAID card fails, will I need to ...
7
votes
2answers
612 views

Can I throttle tar without ionice?

My tar command tar --remove-files -cvif 2011-08-02_14-05-09.tar 2011-08-02_14-05-09 Writes 80MB/s. That's beyond the capacity we can spare because MySQL starts queuing up writes and eventually we ...
7
votes
1answer
16k views

Can Windows 7 do software RAID 10 (1+0)

Can Windows 7 do software RAID 10 (or RAID 1+0 depending on terminology)? There appears to be a lack of information about software RAID for Microsoft Windows products. Even a search of the ...
7
votes
1answer
1k views

Raid 1/10: Kernel panic- not syncing: attempted to kill init

I have setup Raid 1 & Raid 10 in Virtual Box for learning purpose. The following Partitions for 4 Hard Drives: I make a 100mb partition (/boot) on four drives and make that a raid 1 partition. ...
7
votes
2answers
8k views

Boot from software RAID 1 on Windows Server 2008 R2

I have a Windows Server 2008 R2 x64 system with a single hard drive, and I have a spare hard drive of same size/model that's not being used. I was thinking about dropping in the new drive and setting ...
7
votes
2answers
295 views

Linux software raid fails to include one device for one RAID1 array

One of my four Linux software raid arrays drops one of its two devices when I reboot my system. The other three arrays work fine. I am running RAID1 on kernel version 2.6.32-5-amd64. Every time I ...
7
votes
1answer
3k views

Poor Linux software RAID 5 performance with NCQ

While salvaging a 2-disk failure in my 3-disk RAID 5 setup, I happened to notice reconstruction was faster with NCQ disabled (~90M/sec) than with the NCQ enabled (~50M/sec). Running bonnie++ to ...
7
votes
1answer
4k views

High server load - [jbd2/md1-8] using 99.99% IO

I've been having spike in load over the last week. This usually occurs once or twice a day. I've managed to identify from iotop that [jbd2/md1-8] is using 99.99 % IO. During the high load times there ...
6
votes
4answers
2k views

Is it necessary to have RAID in a virtual machine?

I have a Windows 2008 Enterprise on RAID 10 running Active Directory, Hosted Exchange, and a web server on HyperV VMs. Do I need a virtual RAID for Exchange? If so, why? Edit: thanks everyone for the ...
6
votes
7answers
4k views

USB drive RAID array

I am trying to contemplate how stupid an idea this would be... I was inspired by some foolish fellow, who soon after the release of Mac OS X 10.0 took 5 USB floppy drives, plugged them into his iMac, ...
6
votes
5answers
4k views

SW SSD Raid 1 over HW RAID 10

A provider(data center) recommended I go with 1TB SSDs in a software RAID 1 over HW RAID 10 with mechanical drives. Their quote: Typically SSDs are most reliable than RAID cards and since you ...
6
votes
3answers
7k views

explain md's raid10,f2

I know how most of the various RAID's work. But I stumbled on the recommended raid10,f2 mode while researching linux software raid. I don't really understand how it works on 2 or 3 disks. could ...
6
votes
4answers
14k views

How to create a software raid5 array without a spare

I am trying to create a software raid5 array using mdadm: $ linux # mdadm --create --verbose /dev/md0 --level=5 --raid-devices=4 --spare-devices=0 /dev/sda1 /dev/sdb1 /dev/sdc1 /dev/sdd1 mdadm: ...
6
votes
4answers
476 views

mdadm: Replacing array with entirely new drives

I have a server with three 500GB drives, with most of my data in a RAID5 configuration spanning the three of them. I just purchased and installed four 1TB drives, and the intention is to move off of ...
6
votes
4answers
4k views

Do any software RAID solutions support the TRIM command?

This is a broad question -- I'm not asking about a particular RAID level or OS.
6
votes
2answers
6k views

How to do the equivalent of Synology Hybrid Raid on Linux myself?

http://forum.synology.com/wiki/index.php/What_is_Synology_Hybrid_RAID%3F Synology is just Linux and uses LVM. How do their tools automate LVM to achieve what they call their Hybrid Raid?
6
votes
2answers
1k views

How to make a Linux software RAID1 detect disc corruption?

This is one of the nightmare days: A virtualized server running on a Linux SW-RAID1 runs a VM that exhibits random segfaults in seemingly random codechunks. While debugging I find that a file gives ...
6
votes
1answer
674 views

Should I worry about the integrity of my linux software RAID5 after a crash or kernel panic?

I have a dual core Intel i5 Ubuntu Server 10.04 LTS system running kernel 2.6.32-22-server #33-Ubuntu SMP with three 1TB SATA hard drives set up in a RAID5 array using linux md devices. I have read ...
6
votes
1answer
835 views

Linux fails to reassemble RAID array after disk upgrade

I have an Ubuntu (9.10) machine with 4 SATA disks. Each disk is partitioned identically, with the first few gigabytes set aside for a RAID 1 array (/dev/md0) for the boot volume, and the ...
6
votes
1answer
445 views

Where is the best place for LUKS to sit in a RAID/LVM/LUKS stack?

I am implementing a server storage setup making use of software RAID, LVM and LUKS. I can think of three combinations this configuration could take: RAID, LVM, LUKS RAID, LUKS, LVM LUKS, RAID, LVM ...
6
votes
9answers
2k views

2 drives, slow software RAID1 (md)

I've got a server from hetzner.de (EQ4) with 2* SAMSUNG HD753LJ drives (750G 32MB cache). OS is CentOS 5 (x86_64). Drives are combined together into two RAID1 partitions: /dev/md0 which is 512MB ...
5
votes
6answers
4k views

Mac OS X Server 10.6 - Apple's software mirrored RAID worth it?

I am installing an Intel Xserve (Quad core Xeon) with Snow Leopard Server (10.6) on two 80Gb 7200rpm SATA HDs. I created a mirrored RAID set using Disk Utility with those two drives, all went fine. ...
5
votes
2answers
5k views

Where should my swap partition/s live when using software RAID1? Performance? LVM?

When I search around for example RAID1 installations, it seems that admins tend to place their swap partition under RAID1. To me, it is more intuitive to have two disks, each with a large partition ...
5
votes
4answers
3k views

Ubuntu raid - replacing drive?

I've set up software RAID1 with the latest Ubuntu version - 11.04 using two 250GB harddrives which initially worked great. Tried to unplug both and computer still started with degraded raid status - ...
5
votes
2answers
3k views

How to know which disk has failed on a Mirrored Raid? marked as DR0

Our 2ndry DC, which is on a W2K8R2 Mirrored software raid has lost it's sync, and disk management displays the failed redundancy error How do I know which of the disks has failed? (beside to try ...