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 ...
36
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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
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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 1+0,...
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3answers
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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
4k 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 ...
10
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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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3answers
1k 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
10k 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 alone....
6
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2answers
78 views

Is it possible to ask ReFS to use hardware RAID6 for parity calculations?

Does ReFS use FPGA-based XOR engines for RAID parity calculations? If not, is it possible to get it to use such tech?
5
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1answer
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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 ...
5
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1answer
661 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 drives ...
5
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1answer
538 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
882 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 > /proc/...
4
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1answer
413 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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4answers
21k views

Minimum number of disks to implement RAID6

RAID6 is intended to provide fault tolerance in the event 2 disks fail. What is the minimum number of disks required to implement RAID6? thanks
3
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1answer
289 views

recover highly degraded raid array

I have a Linux RAID6 array (mdadm) composed of 8 disks. 2 disks failed. I replaced them, now I have 2 new empty disks. I would like to rebuild the raid but when I start a raid rebuild, the rebuild ...
3
votes
1answer
332 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
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2answers
1k 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
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2answers
4k 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 10TB....
3
votes
1answer
208 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
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1answer
545 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
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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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4answers
447 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
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2answers
107 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
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1answer
15k 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 ...
2
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2answers
260 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
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2answers
401 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
516 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
801 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
0answers
60 views

Recovering an RAID6 using ddrescue. mdadm: failed to add, invalid argument

I had 3 drives fail in a matter of a week on a RAID6. Luckily, one drive seemed to be mostly fine. I was able to run ddrescue and it copied all but one small area (couldn't read 14MB out of 3TB). ...
2
votes
2answers
363 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 ...
2
votes
1answer
322 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
745 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
35 views

How to create degraded raid6 array using megacli

There is a server with few disks. And - a new server with PERC controller. I would like to migrate existing data into a new server to raid6 which uses 6 disks(4+2). Unfortunly - i don't have enought ...
1
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2answers
109 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 ...
1
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1answer
68 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 ...
1
vote
2answers
2k 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 ...
1
vote
1answer
2k views

How is the parity calculation in a RAID 6? [duplicate]

In a RAID5, the parity block is a XOR calculation of the rest of blocks but, in a RAID6, the second block parity is the XOR calculation of what blocks? http://upload.wikimedia.org/wikipedia/commons/...
1
vote
1answer
843 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
364 views

Perc H700 disk rebuild keeps going offline

I have a Dell Poweredge R710 with a Perc H700 Raid controller. It's in a RAID 6 configuration currently with 2 failed disks. It does boot to CentOS in it's currently degraded state. I would like to ...
1
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1answer
92 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; /dev/...
1
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1answer
285 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
67 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 ...
1
vote
3answers
897 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
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1answer
63 views

Linux mdraid RAID 6, disks drop out randomly every few days

I have some servers that run Debian 8 with 8x800GB SSD configured as RAID6. All disks are connected to a LSI-3008 flashed to IT mode. In each server I also have a 2-disk pair as RAID1 for the OS. ...
1
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1answer
62 views

Advice for creating CentOS mdadm software RAID6

EDIT: Solutions to my issue are below I want to create a well optimized RAID6 array with mdadm with an XFS partition on a CentOS system. It'll involve ten ST3000DM001 Seagate 3TB drives and I'll be ...
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1answer
90 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 ...