RAID1 or mirrored RAID uses two disk that have the same data.

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What is the performance implication of hardware vs software RAID in 2-disk RAID0/RAID1 setup?

I am choosing between two similar models of servers, one of which has software RAID, while the other hardware one. Servers in question are SYS-E32-1 and SYS-E32-3 from So you Start (an OVH brand) and ...
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4answers
422 views

Rescue a Raid 1 from a dedicated server

I have a dedicated server (Hetzner EX4). One day, I rebooted the server and it wouldn't start. customer service told me that one of the hard drive was faulty, and activated the rescue system (Linux). ...
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2answers
253 views

Disk Capacity RAID 1 to RAID 10

I have a 4-bay NAS with two 2TB hard drives in a RAID 1 configuration. I was planning to upgrade it with 2 additional 4TB drives to a RAID 10 configuration. Now the new capacity I will receive with ...
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1answer
180 views

How to proceed to switch raid 1 disk from secondary to primary?

I have a Dell PowerEdge T100 server with Windows Server 2008 and raid1 configuration. I've just replaced the secondary disk by a new one. (it was pred fail = yes) Now, the raid1 status is ok and the ...
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2answers
763 views

Dell RAID1 Pred Fail Yes

I have a server with RAID 1 configured that was running too slow.. some applications does not even run. I entered SAS Config. Utility and I checked that RAID 1 was in status 'not synced', but I was ...
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1answer
62 views

Files missing after RAID1 restore

I have encountered unpleasant situation. Given mdadm RAID1 of 2 HDD on server. Yesterday one of HDDs completely dies, other shows bad SMART status but was in accessible state. Mdadm showed "clean, ...
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1answer
692 views

Is it possible to enable RAID 1 on an already in-use HP Proliant DL380 G5

I have a HP Proliant DL380 G5 with two HDDs in RAID 0 (Stripe)(72GB+72GB). It has been running Windows Server for quite a while now and has 30GB of occupied space on a stripted volume. I've now ...
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1answer
239 views

Split a Dell PERC 6/i RAID-1 mirror to temporarily to add additional storage

I need to tidy some disk partitions in Windows Server 2012, but don't have enough storage space, and all drive bays are in use. I'd like to split the mirror, use one of the disks as temporary storage ...
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0answers
4k views

Setting up software RAID 1 on System Partition

I have a Windows 2012 R2 Essentials box I'm building (should be the same concerns as a Server 2012 or Server 2012 R2 box). I'm attempting to mirror the system disk (identical 750GB SATA drives) but I ...
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2answers
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HP DL320e Gen8, 3TB drives, Windows Server 2012 R2 - HDD full capacity alocation difficulties during installation

One interesting task to do but not so easy as i thought. The server is HP DL320e gen8, The main difficulty is with partitioning the RAID1 (2x3TB HDDs) during the installation on 2 partitions (System ...
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1answer
61 views

does raid 1 backup also backup mysql updates?

I have a mirrored RAID 1 server. This server has mysql databases. If I run a query to update a mysql database, does this update also get updated on a RAID 1 mirrored setup or do I need a different way ...
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1answer
138 views

Recovering LVM RAID-1 on different computer with only one drive?

I have a drive out of an old LVM RAID-1 that's been sitting for a while. I think the array contained a bunch of my photos from years ago (archived online) but I'd like to get at the original data and ...
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1answer
44 views

debian stable raid autogrow filesystem database

I need to setup a debian stable system meeting the following needs: Hard disks should be mirroring : Raid 1 Filesystem(s) should autogrow if possible (just in case we replace one hdd with a bigger ...
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3answers
631 views

SQL Server 2012 RAID Setup and Performance [closed]

At my company we are in the process of setting up a new SQL Server 2012 box. We have 6 physical drives with 3,000 gigs each. We are considering two different RAID configurations and are wondering ...
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1answer
168 views

raid 1 always degraded after pushing reset [closed]

I have Marvell hardware raid 1. After pushing reset or any other incorrect shutdown raid is degraded. Is it possible to create hardware raid 1 on other chips(intel chipset for example) for example ...
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1answer
77 views

rsync, dd and then add to RAID 1, could cause database corrupted?

Firstly I have a HDD which has been setup as RAID, type Volume, not RAID 0 or RAID 1 ... and I wanna add one more HDD to setup a RAID 1 array. These bellow steps are what I've done. Detach from ...
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1answer
494 views

LVM RAID 1 for root

I have LVM RAID 1 (not mdadm RAID 1, but exactly LVM2 RAID 1) for my root partition. I would like to make my system boot without either of the HDDs where the underlying PVs of the root LVM partition ...
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1answer
389 views

replacing failed hard disk in raid 1 on dell emc cx300 [closed]

how can I replace failed disk in slot 12 in raid 1 on san dell emc cx300 I HAD Configured the san with hot spare hard disk in slot 13. Is it enough to remove it from it's slot an put instead of it ...
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2answers
234 views

RAID 1 - IOPS Write Penalty 1 or 2

I keep seeing articles describing the RAID IOPS write penalty for RAID 1 (and RAID 10) as 2. RAID 0 would have a penalty of 1, of course, since every write is simply written to disk. RAID 1 is ...
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2answers
2k views

How to delete removed devices from a mdadm RAID1?

I had to replace two hard drives in my RAID1. After adding the two new partitions the old ones are still showing up as removed while the new ones are only added as spare. I've had no luck removing the ...
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2answers
3k views

Clonezilla is not able to clone a RAID 1 disk

I have a HP Server DL320 G5. There are two SATA hard disks configured as RAID 1 through HP embedded RAID controller. Server OS is running GNU/Linux (Fedora) Server booted up with clonezilla live CD. ...
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1answer
531 views

Various problems with software raid1 array built with Samsung 840 Pro SSDs

I am bringing to ServerFault a problem that is tormenting me for 6+ months. I have a CentOS 6 (64bit) server with an md software raid-1 array with 2 x Samsung 840 Pro SSDs (512GB). Problems: ...
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2answers
2k views

How to move RAID 1 to RAID 1+0

I have two HP disks in RAID 1 (300 Gb), and would like to at 2 additional disks in RAID 1+0 having in total of 600 Gb on C:. I would like to know is it possible to do it using Array Configuration ...
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2answers
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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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2answers
103 views

Move CentOS to new raid1 hardware server

I have an existed CentOS server with a normal hard disks (2 disks sda,sdb). They very small. Now I want to update server with a RAID1 hardware and new 2 bigger disks (remove 2 old disk). How can I do ...
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1answer
58 views

Does RAID1 also checks for corruption? [closed]

I have two 1.5 TB disks, and I don't trust both of them because of weird noises and bad clusters. I was wondering if I put them in a software RAID1 array (mirrored volume in Win7) it will write my ...
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1answer
42 views

Access Server 2003 formatted HDD from W7 installation

I have a server problem, not sure what the best approach may be. The scenario is this: OS: Server 2003 The OS was on dedicated IDE drive; there are 2x1TB SATA drives which were in a Windows software ...
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0answers
187 views

Half of disk space missing on RAID1, all disks it seems to be ok

Hi there. I have a problem with raid array. I miss it a half. My disks layout is 2 x 250 gigabytes velociraptors (Array_0000) 2 x 1TB velociraptors (Array_0001) ....both connected in RAID1. OS ...
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2answers
572 views

Remake SW RAID1 from a new HDD and an old HDD with bad blocks

I have a SW RAID1 and I just replaced /dev/sda with a new HDD as the old one failed. Now, upon trying to recreate the RAID array I discovered that the "good" HDD (/dev/sdb) has bad blocks with prevent ...
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1answer
214 views

Saving data on a failing software RAID 1 setup

My CentOS 6 server is running a software RAID 1 configuration with two 1 TB disks. Yesterday trouble started happening when the server was very irresponsive. I checked the logs and noticed a whole ...
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1answer
401 views

RAID1 - Possible to recover failed drives?

PowerEdge 1850 has two physical hard drives, configured as RAID1. Accessing via DRAC 4/I I can see that both drives indicate Failed & Offline. However, the DRAC log indicates that both drives ...
2
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1answer
236 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 ...
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1answer
2k views

DELL Server RAID Exception - Resyncing

Today they brought this old DELL server with 2 HDD initialized in RAID 1 Array. The server was used as a syslog aggregator for a long time and I was tasked to to some maintenance before we return the ...
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2answers
274 views

Possible to build a RAID 1 with only one drive with LSI 9260-4i? [closed]

I have a LSI 9260-4i RAID card plus 1x 300GB Drive. My issue is I have to ship out the server for the 2nd drive to be installed onsite. Can I configure a RAID 1 with only 1 drive, and plug in the ...
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1answer
94 views

Speed up RAID 1 drive read speeds

Sorry I don't know much about this stuff...we have been having issues with a slow server, very slow for users and when you access the server direct, we have added more RAM but it seems it may be a ...
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1answer
1k views

Linux RAID mdadm: what does 'Events' mean?

When I type mdadm --detail /dev/md0 I get a lots of useful information most of which I understand. However I also get a line that reads: Events : 0.710 Where the number varies. Naively, I ...
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2answers
273 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 ...
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1answer
63 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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2answers
213 views

Degraded drive in RAID1 Windows 2008 - system won't boot

I have inherited a Windows 2008 server setup with 2x 160GB Seagate boot drives and 2x Western Digital 1TB data drives. This is one of two servers inside a school. They are three years old and part of ...
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1answer
2k views

Replacing Hard drives/RAID array Dell Poweredge 2900

I have a Dell Poweredge 2900 that I'm upgrading from 4x SATA 250GB Drives in a RAID 5 situation to 2x SATA 1TB Drives in a RAID 1 situation. The box is running Windows Server 2003, with a PERC5/i ...
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1answer
137 views

RAID1: Can I do 'write-mostly' in hardware (LSI type cards) so Drive A: 100% READ and WRITE and Drive B: ONLY WRITE?

The Google hammer has failed me, so I turn to this august body for help :-) I'm interested in doing SSD/HDD RAID1 pairs using the principle of 'write-mostly' as available in Linux's software RAID ...
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1answer
406 views

RAID1 LVM, XEN and flashcache

I am regarding to question: Improving IO with FlashCache I have setup a RAID1 (/dev/md0) LVM (*/dev/vg_xen*) and executed following command: flashcache_create -p thru flashcache0 /dev/sdc /dev/md0 ...
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2answers
260 views

Something wrong with Linux software RAID1

I have a software RAID1 and now every week Linux synchronize my raid volume. I checked cat /proc/mdstat: *Personalities : [raid1] md3 : active raid1 sda5[0] sdb5[1] 1822445428 ...
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How to mount parition in from a working driver in RAID1

One of hard drives in array is dead, I'm unsure if it's raid0 or raid1, what I'm trying to achieve is mount the working drive and make a backup of what's left. If I mount /dev/md127 then I can see ...
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0answers
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Reconfigure from Raid0 to Raid1, is it possible?

currently I have Fujitsu tx140 s1p servers, one Tower and one Rack. They are both running with the same hardware, configures the same way, so I'll just ask one Q for both. They have an motherboard ...
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3answers
224 views

mdadm raid1, drive failure lost 14days worth of data?

I am rather confused. One evening I had a server which had died. I went to reboot it and noticed it was stuck on the "GRUB" boot screen. I then noticed a hard drive had failed. I put a new hard drive ...
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1answer
416 views

“LV Status NOT available” after converting root from lvm2 to lvm2+raid1 (lvconvert --type raid1)

I just converted by lvm2 root filesystem from linear lvm2 (single HDD:sda) to lvm2 raid1 (using lvconvert -m1 --type raid1 /dev/ubuntu/root /dev/sdb5 command). But after this conversion I can't boot ...
2
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1answer
286 views

Replacement raid1 drive is one block smaller. What to do?

Apparently once should always leave a bit of empty space at the end of each raid1 partition. But if we're too late for that, what can be done if a replacement RAID1 drive is slightly smaller than the ...
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3answers
359 views

Raid 0, Raid 1, Raid 5, Raid6, Raid 10 Read/Write performance? [duplicate]

Assume a single disk has a baseline of 1W & 1R performance, how does the different RAID configurations behave? My initial guess: Raid 0: 2W 2R Raid 1: 1W 2R Raid 5: ? ? Raid 6: ? ? Raid 10: ...
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2answers
585 views

LVM mirror with data and logs mirrored on same 2 devices

I'm trying to set LVM mirroring with only 2 devices. It works perfecly when I add third device for mirrorlog, or use corelog. But with only 2 devices and --alloc anywhere LVM nearly always creates ...