RAID, an acronym for Redundant Array of Independent Disks (sometimes incorrectly referred to as Redundant Array of Inexpensive Disks), is a technology that provides increased storage functions and reliability through redundancy. -Wikipedia

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How to remember RAID levels? [duplicate]

How do you remember(if you really do :-)) all the different levels and what each level does? Can anyone suggest an easy way to remember?
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13answers
753 views

Should a sys admin backup important data in anyway he can, even if he disagrees with the backup strategy?

Recently, one of the main file servers at our company failed. It was using a 4 disk RAID array, but apparently 3 of the disks died, and all the data on the server has been lost. Speaking to the sys ...
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2answers
6k views

How to upgrade a ZFS RAID-Z array to larger disks on OpenSolaris?

I'm planning on installing OpenSolaris on my home server (right now it has Linux) and I would like to know how to prepare for upgrading the server to have larger hard drives in the future. Now the ...
9
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1answer
2k views

Managing battery relearn cycles on LSI and similar RAID controllers

How do engineers deal with RAID controller battery "relearn" cycles? As noted in: What's a "battery relearn" on a LSI MegaRaid?, relearn cycle discharges the RAID controller battery ...
9
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1answer
738 views

Why does df shows only half the size of a RAID10 array?

I've created a RAID10 array using 4 75G drives, to create a storage of 150G. After everything finished (including the initial syncing), everything looked good except the output of df -h which showed ...
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2answers
1k views

How to check CentOS 6 Server VM Host after a power falure?

This afternoon, someone at our office decided to pull the plug out of our server because it was storming outside. They didn't shut it down, they just pulled the plug out while it was running. The ...
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2answers
988 views

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 ...
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3answers
2k views

Linux fileserver storage pool

Is it possible to get linux server to share several hard drives as one storage pool through Samba? So that when I use the share I don't have to worry about saving to a certain drive that has free ...
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2answers
2k views

Can different drive speeds and sizes be used in a hardware RAID configuration w/o affecting performance?

Specifically, I have a RAID 1 array configuration with two 500gb 7200rpm SATA drives mirrored as logical drive 1 (a) and two of the same mirrored as logical drive 2 (b). I'd like to add two 1tb ...
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4answers
3k views

One large RAID 10 vs several smaller arrays?

My question is: when is it appropriate to simply create one large array with fast read & write performance, such as RAID 10, instead of creating smaller arrays for specific applications? It ...
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3answers
643 views

Migrate raw disk image over LAN

Here is my situation: Two dedicated servers in the same datacenter with gigabit ethernet between them. Both dedicated servers booted into a rescue environment based on Debian Squeeze with extra ...
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8answers
11k views

How to Monitor an Adaptec/Intel ICH10R RAID Controller (any SNMP notification options?)

SuperMicro's Super Doctor III is the software I was looking for. It is SuperMicro's equivalent of IBM's ServerGuide or Dell's OpenManage. Unfortunately, while it supports hardware monitoring and SNMP ...
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2answers
786 views

Linux RAID-0 performance doesn't scale up over 1 GB/s

I have trouble getting the max throughput out of my setup. The hardware is as follow : dual Quad-Core AMD Opteron(tm) Processor 2376 16 GB DDR2 ECC RAM dual Adaptec 52245 RAID controllers 48 1 TB ...
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2answers
864 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 ...
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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 ...
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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 ...
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7answers
5k views

Can I just remove a disk from a live RAID 1 array?

I've read the story about the manager taking out a disk from a RAID 5 array, and then a second one, but I’d just like to try out for myself what happens when I simply disconnect a disk from a live ...
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4answers
4k views

RAID 1+0 vs RAID 0+1

I went with some advice I was given from someone I know to go with a RAID setup for this server I ordered. The specs are below. I plan on using this server to host multiple sites in a PHP/MySQL ...
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6answers
42k 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. ...
7
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4answers
14k views

Why do I need a raid battery pack?

I'm trying to understand why one would add a batterypack to a raid card. It seems to me like if power goes down, running just the raid card is going to do little good: without power for HDs and ...
7
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2answers
2k views

Large RAID stripe size wastes space with small files?

I'm planning a Maildir storage with RAID 0+1(or RAID 10, RAID 5) on XFS filesystem and XFS will be created with stripe unit and width that RAID will use. I don't determine RAID stripe size yet, but ...
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1answer
7k views

How exactly does a SAS SFF-8087 breakout cable work? + RAID/connection questions

Please let me know if my question does not makes any sense as I am not sure if I am interpreting it correctly from my thoughts due to my lack of technical knowledge on this. If I am using a ...
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3answers
2k views

Do I need a second RAID controller for fault-tolerance?

I have a server with 3 hard drives installed, and a total capacity of 6. We're planning to max it out, but our consultant also suggested getting a second RAID controller "for redundancy" to support ...
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8answers
700 views

Recommendations for hardware RAID controllers [closed]

I'm looking for a hardware RAID controller. I want something that: Can support 8 or maybe 16 hard drives Won't randomly break, lose my data, etc. Does anyone have recommendations? It seems like ...
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3answers
685 views

RAID array Considerations - Any advice?

We just bought a Dell PowerEdge r510 (12 drive bays) that will fill the role of an archive server. We have 6 drives (1TB each) installed. The plan is to have all the drives in a single RAID array and ...
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1answer
3k views

Can I create a “soft” RAID1 array without nuking data?

I've just bought two 1.5TB disks with the aim of creating a 1.5TB RAID1 array. In my infinite lack of wisdom (and a lack of space inside the computer - it already had 6 disks), I stuck one in, ...
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3answers
32k views

How to find RAID configuration/level and RPM speed having only remote access to the server?

Having only remote access (no physical access), to a server (that is SSH), how do I (or may be is it possible): find out whether it is RAID configured or not? If it is RAID configured, whether it ...
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3answers
12k views

What does 3Ware's tw_cli mean by a “DEGRADED” disk vs “ECC-ERROR”?

I've got a sad RAID array on a 3ware 9650SE-16ML card. What I can't tell is if I've just suffered a double-disk failure (bummer!) or if I'm reading this wrong. The relavent output of /c0 show all ...
7
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3answers
857 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
1answer
10k views

Megacli is killing me, any help appreciated

I run a server with 2 drives in raid0 configured through BIOS. I just added 2 more drives using hotplug (the server is dell r610 with RHEL 5.4 64bit) and I would like to configure a separate raid0 ...
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5answers
837 views

For a server that can tolerate downtime, is it better to use a hot spare or a cold spare?

In other words, should I leave a spare disk on the shelf or set it up as a hot spare? If the server has a little bit of downtime, it isn't the end of the world. It's not a webserver or anything that ...
7
votes
2answers
353 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
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4answers
61k views

How to check if hardware RAID is configured?

I have several servers running Windows 2008 and Red Hat 5 that are capable of hardware RAID. How do I check that hardware RAID is configured?
7
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3answers
2k views

Restoring an Amazon EBS RAID0 array from snapshots taken with ec2-consistent-snapshot

I've configured a new MySQL server on Amazon EC2 and decided to store my data on a EBS RAID0 Array. So far so good, and I've tested taking snapshots of those devices with ec2-consistent-snapshot, ...
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5answers
5k views

Squid or Other HTTP Caches with SSD Cache Store?

I'm contemplating setting up a squid (or possibly varnish) cache on a system with SSD drives. The obvious benefit is that these systems have great READ speeds and I expect my hit ratios to be fairly ...
7
votes
2answers
498 views

convert 1x2TB HDD with LVM into 2x2TB HDD with RAID1+LVM or with LVM mirroring?

I have Ubuntu server with 1x2TB HDD and 1x128GB SSD (unused). There are 2 partitions: /boot, and a physical volume for LVM, which has 1 group and 5 logical volumes: /, /var/log, /home, /srv, /tmp. ...
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4answers
22k views

kernel: journal commit I/O error

I am having some problems with a Dell 1950 server. I am installing RHEL 4.6 along with Oracle and some other software on here. I am randomly getting an error message saying "kernel: journal commit ...
7
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3answers
709 views

growing a raid z(1/2)

I'm planning on building a fileserver on top of opensolaris, using either a raid z1 or z2. Is it possible to later upgrade a disk at a time and immediately have access to the increased storage? Or ...
7
votes
1answer
14k 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
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1answer
3k views

How to select the best Stripe Size when configuring a RAID Array

There are various "references" on the Internet that delve into some discussion about what factors to consider when selecting a particular RAID stripe size (4KB to 128KB or more) for an array of disks, ...
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1answer
350 views

Which block sizes for millions of small files

I have 2x 4TB Disks in hardware RAID1 (it might be a LSI MegaRaid) on Debian Wheezy. The physical block size is 4kB. I'm going to store 150-200 million of small files (between 3 and 10kB). I'm not ...
7
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2answers
4k views

LSI 9285-8e and Supermicro SC837E26-RJBOD1 duplicate enclosure ID and slot numbers

I am working with 2 x Supermicro SC837E26-RJBOD1 chassis connected to a single LSI 9285-8e card in a Supermicro 1U host. There are 28 drives in each chassis for a total of 56 drives in 28 RAID1 ...
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3answers
2k views

Will spinning down hard disks create Linux Raid problems?

I'm setting up a server that will need to be accessible 24/7 but will be rarely accessed (archive storage). To save heat/power, I'm thinking of setting hard disks to spin down using hdparm. However, ...
7
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1answer
334 views

RAID with 4 drives offers very minimal speed improvement

Setup 1.5TB x 8 on a SANS Digital enclosure configured into two sets of 4 drives and connected to a Windows Server 2003 computer over eSATA. They are all identical Seagate Barracuda ST31500341AS ...
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votes
11answers
12k views

Most efficient RAID configuration with 6 disks?

I have a hand-me-down server that I'm setting up at home and it's got 6 72Gb hard disks (as well as 2 18Gb drives that I'm using for the OS). What is the best way to configure those 6 drives? Should ...
6
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4answers
295 views

Why are there RAID models where there are more than one parity disk?

I was just wondering how multiple "parity disks" would work, since it seems that doing so might defeat the purpose of having a parity.
6
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8answers
2k views

24TB RAID 6 configuration

I am in charge of a new website in a niche industry that stores lots of data (10+ TB per client, growing to 2 or 3 clients soon). We are considering ordering about $5000 worth of 3TB drives (10 in a ...
6
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6answers
685 views

RAID 0 recovery

I know the theoretical answer is "not possible". But theory and practice do not always match. So I'm wondering if you know any trick to recover something... Is there any chance to recover anything ...
6
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3answers
5k views

What purpose does the battery serve on a battery-backed caching RAID controller if the server is on an uninterruptible power supply?

Is the battery redundant if the server is on a properly-sized UPS? There is an option to force write-back mode and I want to understand the risk. It is my understanding that it helps against power ...