RAID solution handled by the operating system.

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3
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1answer
2k views

Linux file system cache: Move data from Dirty to Writeback

My software RAID can write 800 MB/s sustained. I see that happening when cat /proc/meminfo |grep Writeback: returns > 2 GB. However, most of the time the writeback is round 0.5 GB which gives a ...
2
votes
1answer
153 views

Linux: md Software RAID array out of sync

We had a CentOS server report this software RAID issue via /etc/cron.weekly/99-raid-check WARNING: mismatch_cnt is not 0 on /dev/md2
1
vote
1answer
397 views

Failing disks in RAID array - strategy suggestions required

I have a linux based software RAID 5 array. SMART has just started to send me emails complaining that one of the 5 disks has a Current Pending Sector Count of 9 and also an Offline Uncorrectable Count ...
0
votes
1answer
124 views

Add generic rescue kernel on Gentoo

I have a Gentoo machine (64-bit) with software RAID on boot which was set up previously by someone who optimised the kernel for that machine. Now I want to shift the disks to a new machine (also ...
1
vote
1answer
280 views

Linux software RAID 10 array, failed drive, resize file system and migrate to a 3 drive RAID 1?

I have a software RAID 10 array which I recently noticed went into a degraded state. The OS is CentOS 5.8. It has 4x 500GB drives in 3 different arrays: /dev/md0 is RAID 1 and mounted to /boot (200MB ...
0
votes
1answer
586 views

Device in software RAID 10 array: clean, degraded. Ouch?

I've got 4x 500GB drives in software RAID. /dev/md0 is RAID 1 and mounted to /boot /dev/md1 is RAID 10 and is swap /dev/md2 is RAID 10 and is the main system and data device I looked at mdadm this ...
1
vote
1answer
210 views

What would happen if the underlying OS running software RAID crashed?

For example, if I had either a Linux server running mdadm or Windows OS performing RAID at the software level, would data recovery be possible if the system crashed? Are there tools to access the ...
3
votes
1answer
580 views

How do I preseed a simple RAID5 setup on Ubuntu Server? [closed]

I have three 2TB drives in the machine; I want a RAID5 of ~4TB capacity, and 100GB or so of swap space. No LVM, no encryption, no fanciness. This is easy to do using the interactive installer, but I'm ...
0
votes
1answer
247 views

Linux RAID10 hit bad disk while re-syncing. Is it hosed?

I have a Linux software RAID10 device on md0. It's made up of 4 1TB disks sd[abcd]. Yesterday Smart emailed me to say a disk was going bad (seek errors going up and reallocated sectors). I rebooted ...
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vote
0answers
153 views

mdadm drive UUIDs chanaged, can they be changed back?

So I ran into this trouble and I believe I lost all my data..However I found an old mdadm --examine --scan file I made a month ago and an old mdadm.conf....Is it possible to use these two items to fix ...
1
vote
2answers
7k views

mdadm rebooted, array missing? can't assemble?

Not sure what is going on with my Array. I rebooted ubuntu 12.04.1 and got a error on startup that fstab couldn't mount the filesystem UUID I have for my mdadm array. After running a few commands a I ...
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votes
2answers
146 views

How do RAID 0 Offers improved i/0? [duplicate]

Possible Duplicate: What are the different widely used RAID levels and when should I consider them? I wonder how RAID 0 offers better i/o. If i am not wrong in RAID 0 data gets split and ...
0
votes
2answers
461 views

Mid-2011 Mac Mini Server keeps dropping a disk from RAID, not sure what to do about it

The small business that I do sysadmin work for on the side uses a mid-2011 Mac Mini Server (running 10.7 Lion) as a fileserver and FileMaker database host. Its 2 750gb HDDs are RAID 1'd together, and ...
1
vote
1answer
67 views

Adding Raid 1 to Raid 0 on Linux

I have a system already configured with raid 1 with 2 disks: /dev/md1 918347072 249416692 621528596 29% /var /dev/md0 9920532 160640 9247828 2% /tmp # cat ...
5
votes
1answer
2k views

High I/O latency with software RAID, LUKS encrypted and LVM partitioned KVM setup

I found out a performance problems with a Mumble server, which I described in a previous question are caused by an I/O latency problem of unknown origin. As I have no idea what is causing this and how ...
3
votes
1answer
1k views

Removing a device in “removed” state from Linux software RAID array

My workstation has two disks(/dev/sd[ab]), both with similar partitioning. /dev/sdb failed, and cat /proc/mdstat stopped showing the second sdb partition. I ran mdadm --fail and mdadm --remove for ...
4
votes
2answers
415 views

Windows Server 2008 Software Raid 5 - Data integrity issues

I've got a server running Windows Server 2008 R2, with a (windows native) software raid-5 array. The array consists of 7x 1TB Western Digital RE3 and RE4 drives. I have offline backups of this array. ...
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0answers
78 views

Single drive LVM to RAID6 LVM

I cloned my entire LVM volume group from a single drive to a RAID5 array with 3 disks. The VG is formed by these logical volumes: root swap home ... and other volumes of some XEN virtual machines. ...
2
votes
2answers
309 views

How do I find out which disk in a multi-disk mdadm RAID1 triggered a rebuild?

I'm using mdadm for several RAID1 mirrors. md7 is an N-way mirror consisting of 3 spinning disks (all flagged write-mostly) and an SSD: md7 : active raid1 sdd1[0] sde5[3](W) sdf5[4](W) sdc1[1](W) ...
3
votes
2answers
229 views

Linux software RAID - partition first?

I have two identical drives that I intend to mirror in in the interest of data safety. These are data-only drives, not a primary OS drive. In such a system, is it better to create single partition ...
0
votes
2answers
650 views

iSCSI Distributed RAID?

Thinking about setting-up as distributed RAID array over iSCSI. Has anyone else tried this, if so what was your experience. To be more specific I am thinking of a couple of CentOS servers each with ...
5
votes
2answers
539 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 > ...
0
votes
1answer
386 views

Raid 10 - Very slow [closed]

I have Software Raid 10 setup, it has been working great a few months. When I did a quick HD speed test: dd if=/dev/zero of=test bs=64k count=16k conv=fdatasync It is taking forever and I had to ...
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vote
0answers
288 views

Reusing slot numbers in Linux software RAID arrays

When a hard disk drive in one of my Linux machines failed, I took the opportunity to migrate from RAID5 to a 6-disk software RAID6 array. At the time of the migration I did not have all 6 drives - ...
1
vote
2answers
732 views

Linking FreeNAS Boxes

I have two different FreeNAS boxes that are being used for storage. It is possible to link them in a manner that the linked connection can be presented as a single storage destination for clients? ...
4
votes
1answer
1k views

mdadm+zfs vs mdadm+lvm

This may be a naive question since I'm new to this and I cannot find any results about mdadm+zfs, but after some testing it seems it might work: The use case is a server with RAID6 for some data that ...
1
vote
1answer
839 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
2k views

Create mirror software raid with bad blocks hdd. How to check data integrity?

There is error in System event log like this one: "The device, \Device\Harddisk1\DR1, has a bad block." Because of above I created Raid 1 on this disk and other one. I'm using Windows Server 2008 R2 ...
3
votes
2answers
455 views

From which plex am I booted from on raid?

I have a server with mirrored boot volume. It is software raid 1 in Windows Server 2008 R2. I do not have physical access to the server. I am looking for a way to check which disk is a boot drive. I ...
3
votes
2answers
700 views

Linux Software RAID1 Rebuild Completes, but after reboot, its degraded again

I have been beating my head with an issue here, and I'm now turning to the internet for help. I have a system running Mandrake Linux, with the following configuration: /dev/hda - This is a IDE ...
0
votes
2answers
501 views

How to Detect Hard Disk Failure

I have a software RAID 1 setup in my CentOS 6.2 and set to be bootable in any of the HDDs in case one of them fails. Questions: How can I recognize if one of the HDDs fail? or early signs of ...
3
votes
2answers
3k views

Can't boot after Disk 0 of software raid is replaced

On a windows 2008 R2, which was on a mirrored software raid, Disk 0 has failed. After I replaced it with an alternate drive (can not find the same capacity and model) - the server isn't booting. ...
5
votes
2answers
2k 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 ...
1
vote
1answer
615 views

Controlling mdadm faulty disk rebuild order in RAID 10 array

I have a Linux mdadm RAID 10 array comprising of 6 (SATA) disks configured with n2 copies. While pulling out one disk, another one in another mirror pair failed. Leaving me with: $ cat /proc/mdstat ...
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votes
1answer
96 views

HDrecover on soft raid arrays

I recently used hdrecover to repair a disk and it successfully repaired three bad sectors. How does hdrepair function on raid arrays, is it likely to break the array by repairing sectors?
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vote
2answers
562 views

Risky to have RAID5 with 3x3TB drives? What alternatives should I be considering?

A drive dropped out of my raid 5 array yesterday. It looks like the reason was due to a bad controller so I switched it out and attempted to re-add the drive but mdadm claimed it couldn't do it. So I ...
1
vote
1answer
120 views

Converting software RAID1 to RAID10 for /boot

Array info: /dev/md0 -> /dev/sda1 and /dev/sdb1 /dev/md2 -> /dev/sda2 and /dev/sdb2 Partition info: /boot -> /dev/md0 / -> /dev/md1 I have two drives that are setup as RAID1 using software RAID ...
1
vote
1answer
1k views

Cannot reactivate RAID-5 volume: The size of the plex member is invalid

We had a 3-drive Windows Server 2008 R2 RAID-5 fail (operating in redundancy mode): WDC 1 TB WDC 1 TB WDC 1 TB We removed the failed hard drive, and put a WDC 1 TB drive (that we had standing by) ...
1
vote
1answer
1k views

Linux Software RAID: How to fsck on hard drive?

We have a Linux server running with Software RAID1. We see some issues in /var/log/messages like: unreadable sector. I want to perform a complete fsck on the drive to get some more information, but a ...
3
votes
1answer
399 views

mdadm kernel log messages explained

Welcome. I try to recover from linux software raid failure. I am in a process of recreating the superblocks based on a syslog from the system when it was healthy. The log speaks about 2 md devices, ...
1
vote
1answer
683 views

What parameters to mdadm, to re-create md device with payload starting at 0x22000 position on backing storage?

I try to recover from mdadm raid disaster, which happened when moving from ubuntu server 10.04 to 12.04. I know the correct order of devices from dmesg log, but given this information, I still cannot ...
0
votes
1answer
92 views

How many really distinct permutations of volumes are in mdadm raid5 degraded array?

I'm attempting to recover from a failure of my raid volume after upgrade from ubuntu 10.04 to 12.04. I've tried re-creating the array in any combination of 5 elementary volumes with one replaced ...
5
votes
1answer
959 views

What effect does RAID stripe size have on read-ahead settings?

I'm trying to figure out the correct read-ahead values to set on a RAID10 array, and I'm wondering if the RAID stripe size should factor into my considerations. I've heard conflicting information ...
0
votes
1answer
89 views

Linux Software RAID 1 issue

I recently had a HDD failure on a SW RAID1 system (Debian 6.0) and what happened was that the active HDD looked like it had some badblocks which somehow propagated to the HDD that was still OK but it ...
5
votes
1answer
9k 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 ...
1
vote
1answer
129 views

grub2 failing to detect md0 for /

I recently set up a raid 1 array. Both / and /boot are on md0 (sda, sdb). everything was working when it was in degraded mode before I synced the two disks together. It was booting from grub2 on ...
-1
votes
1answer
139 views

Software raid 0 with six disks performance

I have some problems with disk performance. I have 6 x WD 500Gb RE4 disks. Each disk gives 135Mb/sec throughput. All measurements are made with hdparm with options "-tT" (I know that it is just ...
0
votes
1answer
1k views

Linux software RAID60: Can I have global hot spare?

As far as I can see Linux has RAID6 and RAID0, but not RAID60. So RAID60 is emulated by creating RAID0 on top of some RAID6s. It is possible to add a hot spare to each of the RAID6s, but is it ...
0
votes
1answer
5k views

Why has ESXi 5.0 not used the software RAID configuration on my test server?

I've got a test server which was running WS 2008 Enterprise on the bare metal. It was correctly using the software RAID 1 configuration (2x250 GB disks which appeared as one disk), setup on the Dell ...
0
votes
1answer
471 views

Ubuntu server boot degraded raid

I've installed Ubuntu 12.04.1 in a new server and set up the 4 hard drives with 3 RAID 1 devices, the configuration is such that the first two drives have md0 (swap space) and md1 (/) with the third ...