RAID6 is a method of configuring fault-tolerant hard drive storage. It is similar to RAID5, but differs in that it writes two sets of parity information, thus can survive the simultaneous failure of two hard drives.

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How bad is it really to install Linux on one big partition?

We will be running CentOS 7 on our new server. We have 6 x 300GB drives in raid6 internal to the server. (Storage is largely external in the form of a 40TB raid box.) The internal volume comes to ...
29
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10answers
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Which is better: RAID5 + 1 Hotspare / RAID6? [closed]

Just curious, I have 6 x 1TB 7200RPM Near Line SAS for my new server. I can either configure it as RAID5+1 Hot Spare or RAID6. What should I choose?
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6answers
3k views

Why is RAID 1+6 not a more common layout?

Why are the nested RAID levels 1+5 or 1+6 almost unheard of? The nested RAID levels Wikipedia article is currently missing their sections. I don't understand why they are not more common than RAID ...
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2answers
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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 ...
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2answers
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Areca 1280ml RAID6 volume set failed

Today we hit some kind of worst case scenario and are open to any kind of good ideas. Here is our problem: We are using several dedicated storage servers to host our virtual machines. Before I ...
8
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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 ...
7
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3answers
985 views

Is it safe to write data to a RAID 6 while it's rebuilding?

I have a test RAID controller on my network which hosts a very large RAID 6 (11 drives, 3TB each). One of the drives failed, and the array is now rebuilding. At this rate, I think it will take about 3 ...
6
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2answers
7k views

Convert a Smart Array RAID5 array to a RAID6 (ADG) variant

I have an HP MicroServer (N36L) with a SmartArray P410 controller, a 512MB BBWC unit and four (4) 2TB disks connected. Three of those disks are configured as a single RAID5 array and one is left ...
5
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1answer
438 views

Linux mdadm --grow RAID6: Something wrong - reshape aborted

I have a RAID60 that I want to expand. The current is: 2 axles each having 9 disks + 2 spares. The future is: 4 axles each having 10 disks + 1 spare. So I need to do some --grow to reshape the ...
5
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2answers
705 views

Linux software RAID6: rebuild slow

I am trying to find the bottleneck in the rebuilding of a software raid6. ## Pause rebuilding when measuring raw I/O performance # echo 1 > /proc/sys/dev/raid/speed_limit_min # echo 1 > ...
4
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1answer
4k views

3Ware 9650SE RAID-6, two degraded drives, one ECC, rebuild stuck

This morning I came in the office to discover that two of the drives on a RAID-6, 3ware 9650SE controller were marked as degraded and it was rebuilding the array. After getting to about 4%, it got ...
4
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1answer
396 views

3 drives fell out of Raid6 mdadm - rebuilding?

i had an mdadm raid6 array with 13x1TB drives. Within 10 minutes 3 of these drives fell out of the array... we assume bad cable to the controller card and replaced, however now we need to get the ...
3
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1answer
288 views

Abort raid6 expansion on Adaptec 52445 SATA RAID?

I am expanding my raid6 array from 18x2Tb to 20x2Tb disks and after 3 weeks status shows: Logical device Task: Logical device : 0 Task ID : 105 Current ...
3
votes
2answers
934 views

How to diagnose intermittently slow raid data transfer rate?

I have an encrypted RAID6 set up on Centos 5.5. When I transfer a large 10gb file from the raid to my computer it will pause at around 4-5gb and again at 9gb. The data transfer drops from 25mb/sec to ...
3
votes
1answer
561 views

RAID-5 or RAID-6 - is RAID-5 really that bad? [duplicate]

Possible Duplicate: Which is better: RAID5 + 1 Hotspare / RAID6? I need to decide myself between RAID5 and RAID6. The servers have a hardware-RAID controller and 6 drives each. The ...
3
votes
1answer
202 views

mdadm raid6 recovery reads more from one drive?

I just replaced a fault drive in my raid6-array (consisting of 8 drives) during the recovery I did notice something strange in iostat. All drives are getting the same speeds (as expected) except for ...
3
votes
1answer
258 views

Backup Solutions for 20 TB of data [duplicate]

First, some background on out situation. We're a small-medium business who has around 20 TB of data on two different NAS's, and that number grows by at least 10% annually. 90% of this data we need to ...
2
votes
4answers
411 views

Which RAID format is best for data privacy during RMA?

So there are several RAID configurations to chose from, and I was wondering, eventually I expect some 25-45% of my drives may need to get swapped for a warranty repair. I know that there is no hope ...
2
votes
2answers
97 views

Progressive upgrade of a RAID array

I have a 16 disk backup RAID6 array. Currently, those 16 disks have the following specs; 500 GB 16 and 64MB cache 3 Gb/s SATA I would like to begin upgrading these disks if possible, primarily ...
2
votes
2answers
253 views

Remove second RAID6 drive during resync from first failure?

I have a RAID6 comprised of five 1TB drives in good working order. I'd like to redistribute the array differently in my system (change the drive distribution over controller cards). I pulled the first ...
2
votes
5answers
2k views

Which disk is bad in raid6 array

Server: Ubuntu Lucid RAID controller: Adaptec 3805 8 disks in RAID6 on HP Proliant DL180 G5 Hardware My kern.log tells me that I have an error on sdb, as shown below: [2740390.344436] sd 4:0:1:0: ...
2
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1answer
177 views

mdadm RAID6 to RAID60

Is it easy to convert a RAID6 to a RAID60? Right now, I have an 8-drive RAID6. I'm looking to upgrade to a 3U 16-bay system and thinking of having a 16-drive RAID60. Is it possible to move my ...
2
votes
1answer
315 views

Concerns of simultaneous failure of SSD Raid1

Since SSD's have a write limit requiring wear leveling one would assume that all things being equal 2 identical SSD drives would wear nearly identically if they mirror data writes. When one drive ...
2
votes
2answers
644 views

Strange performance issue with Dell R7610 and LSI 2208 RAID controller

Connecting controller to any of the three PCIe x16 slots yield choppy read performance around 750 MB/sec Lowly PCIe x4 slot yields steady 1.2 GB/sec read Given same files, same Windows Server 2008 ...
2
votes
1answer
198 views

Expanding RAID6 with LVM

My question is a bit broader than the question title, but here is my situation: I have Synology Hybrid Raid (SHR) built on 2 x 2TB drives. I want to migrate to a software-RAID on a homegrown linux ...
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5answers
1k views

RAID 6 to RAID 1 with mdadm

My home network is changing and I am moving my file storage solution away from my Ubuntu server and onto a Drobo FS. I currently have 6 500GB hard drives in a RAID 6 array providing 2TB of capacity. ...
1
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1answer
580 views

recovering a corrupt degraded btrfs RAID6, need to manually clear an inode

I have a btrfs RAID 6. I have lousy hard drives, one failed, and another failed during recovery. Now I am without parity and cannot rebuild--a third drive is throwing read errors on a few sectors. ...
1
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1answer
10k views

LSI MegaRaid warning: Patrol Read can't be started

We run a HyperV server on RAID-6 (the OS is Windows Server 2008 R2). The hardware is LSI MegaRaid SAS 8704EM2 controller, with 4x 1TB WesternDigital SATA drives. The server is up & running on this ...
1
vote
2answers
54 views

RAID 6 - any write amplification in 4-drive RAID?

We're planning to move from a 4-drive RAID6 to a SSD RAID 1, and I was analyzing smartctl data to see how many GB we've writen to the drives over the past year so I can estimate the lifetime of the ...
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2answers
1k views

ZFS: 3 devices: what's the difference between mirror and raidz2?

It would seem like with 3 devices, it's possible to configure a ZFS pool with either mirror or raidz2 mode. What's the difference in performance and reliability? (In regards to reliability, I'm ...
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1answer
625 views

Using 2-port LSI 9286-8e card to control 24 SAS HDDs

I would like to rely on a RAID-on-chip solution to control 24 SAS hard drives in a direct-attached environment. How would you approach this to get best bandwidth given that I'd like to spend less ...
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3answers
2k views

RAID Virtual Disk Configuration / Partitioning in Operating System?

I have 6 x 1TB SAS for my new server. I want to create 3 partitions: one for OS, one for Virtual Machines, one for share data. There are 2 options for me: Option A: Create 3 Virtual Disks in RAID ...
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1answer
82 views

First 500MB of RAID6 array is wiped, how to recover?

We have a RAID6 array with 12 disks on a 3ware 9650SE-12ML controller. An engineer of our server provider issued this command by mistake: sudo dd if=/dev/zero of=/dev/sde bs=1M count=500; sync; ...
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1answer
211 views

mdadm raid6 array reports incorrect size in df -h after grow

I've recently grown a 5x 3tb mdadm raid6 array (8tb) with a sixth disc in fedora 18, and after full rebuild and check, "mdadm --detail /dev/md127" returns the below: Version : 1.2 Creation ...
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1answer
64 views

Safest approach when designing storage server [duplicate]

We are planing cloud solution for our customers and we are really concerned with designing safest storage servers for their files. This storage won't be IO demanding, as it will contain only files ...
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1answer
1k views

Linux software RAID6: 3 drives offline - how to force online?

This is similar to 3 drives fell out of Raid6 mdadm - rebuilding? except that it is not due to a failing cable. Instead the 3rd drive fell offline during rebuild of another drive. The drive failed ...
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2answers
2k views

RAID6 setup - adding additional drives

I want to setup a dedicated server. To begin with we need a minimum of 8TB. I believe I can begin with 6x2TB drives in a RAID6 setup to achieve this. Now when I need to increase this capacity to ...
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vote
3answers
876 views

mdadm & raid6: does “re-create(with different chunk size) + resync” destroy orig. data?

I would like to rescue data on my software raid-6 array. I did some stupid actions (described bellow) with this original array. Main Question: I need to know if original data stored on raid-6 array ...
1
vote
2answers
71 views

mdadm RAID6, recover 2 disk failure during reshape

I was reshaping my array from 10 disks to 11 to a degraded state (drive I want to add already has data on it, but nowhere to put it). 2 drives disconnected while it was running (power issue). Is it ...
1
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1answer
65 views

Linux soft RAID6 how to identify last failing drive [duplicate]

I have a RAID6 array that had been neglected, and just had the third drive fail. I want to do a ddrescue of the last drive to fail to try to recover the RAID, however I don't know how to identify ...
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0answers
134 views

RAID6 Ubuntu rebuild - how to calculate best parameters for fastest rebuild

I am doing a resync on a RAID6 array and I am looking at some 2 days to complete. I looked here for hints on how to speed it up, but I have, instead, managed to slow it down! HW details are: 10x 4TB ...
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0answers
177 views

Need help recovering RAID 6 array

My CentOS 6.5 server had its primary drive fail the other day. Our hosting company replaced the primary drive and reinstalled the OS. The system is up and running, but the 15TB of RAID6 storage isn't ...
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0answers
32 views

Which Inode Size for Files bigger than 60mb

I will create a new server and wondered about the I-node options default, news, large file and largefile4. I searched the net and found explanations about 256kb until 4mb for one I-node, but i cant ...
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0answers
117 views

Online expansion PERC700 RAID6 server

I have a Dell PowerEdge r510, with 5 HDDs in a RAID6 configuration. I'd like to add a 6th disk (and, in the future, more) to grow the hardware RAID configuration. I have a logical volume, in which ...
1
vote
1answer
558 views

esx4 vmfs3 raid rebuild

I have a ESX 4.1 Server with a storage on RAID 60. After the rebuilding of the RAID the vmdk-files are not working in my VM. On starting VM I have this error: Cannot open the disk ...
0
votes
7answers
791 views

Which RAID/LVM configuration for new 2x8TB file server is safest?

I just built a totally new PC to be a fileserver. It has one 60gb SSD for OS (ubuntu 12.04), and 8 2tb data drives in it. I am looking for the safest, most stable way to set up a single giant ...
0
votes
2answers
97 views

soft raid6 recover second disk fault

I had a disk failure in a hosted system and had the failed drive replaced. During recovery, a disk error on a different drive occurred. when the original error occurred: md2 : active raid6 ...
0
votes
1answer
1k views

3ware raid controller, unit unusable, several degraded disks

I was switching the disk drives in my server, running RAID 6 on 5 disks on a 3ware 9650SE controller, for newer disks and have run into a problem. The two first disks went fine, I took out one disk ...
0
votes
2answers
66 views

Raid 6 with HP P421?

I cant figure out if I need to buy a licens key to enable Raid 6 for this raid controller? I can't find where to buy one and I find pages where it says that its now free. sudo hpssacli ctrl slot=1 ...
0
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1answer
56 views

Running RAID 6 with a smaller drive

It looks like one of my hard drives failed in our RAID 6 (4 x 2TB) configuration. Unfortunately, I only have immediate access to a 1TB drive. Would there be an issue with temporarily replacing the 2TB ...