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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4
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2answers
14k views

HP ProLiant ML350 G6: Does the RAID rebuild automatically?

A SAS HDD in our ML350 is faulty. We're buying a new one and I wanted to ask if I can just take out the faulty one and insert the new one with the server on to let it rebuild the raid or any manual ...
3
votes
1answer
6k views

How do I migrate disks from one Dell PE 2850 to another?

I had a Dell PE 2850 die and I need to move its SCSI disks over to another PE 2850. These disks were in RAID1. I tried moving them over and just hoping the PERC would do the right thing, but it didn'...
1
vote
4answers
839 views

Can someone explain the physical architecture of RAID 10 in complete layman's terms? [duplicate]

I am a newbie in the world of storage and I am having a hard time digesting the physical architecture of some of the RAID levels. I am particularly interested in RAID 10, and 50. I asked the question ...
1
vote
2answers
396 views

Proliant raid controller in a PC

Does anyone know or have experience installing an HP array controller in a standard PC? I'm interested if it would be possible to use a P400i with a SAS-SATA cable using standard Western digital ...
1
vote
2answers
12k views

LSI RAID monitor reports “Consistency Check inconsistency logging disabled”

I have a server with a LSI MegaRAID 9261-8i controller. Recently I started getting alerts like this one: Controller ID: 1 Consistency Check inconsistency logging disabled, too many ...
1
vote
3answers
1k views

Why is the 9650SE RAID1 not showing the full size of the disks?

This is a follow-on to How can I grow a 3Ware 9650SE RAID1 under ESXi 5.0? I've successively replaced 1TB drives in my RAID1 with 2TB drives hoping that I can grow the datastore I've got in ESXi 5.0. ...
1
vote
3answers
2k views

HP DL585 G1 with VMware ESXi 5 - SATA solution, need more storage

I have the following: 2 x DL585 G1 (8 cores) with built in Smart Array 5i (2 x 74GB SCSI in Raid 0) I installed VMware ESXi 5 and got it all working :) However I need more space. I was thinking ...
0
votes
1answer
377 views

Move raided hard drives between identical servers, preserving data

I have a raid array of hard drives in a Sun x4600 that need to be moved out, and another Sun x4600 ready to accept those hard drives. The problem is: in my limited experience with servers, it seems ...
0
votes
2answers
2k views

Is it possible to run LSI SAS 9211-8i PCI-E 8 in PCI-E 16 Slot?

I just bought an LSI SAS 9211-8i HBA(Host bus adapter) to use with my new hardware. I realized after looking at the card that it required an x8 slot and my new mobo only x16 available. I keep on ...
36
votes
8answers
62k views

How to interrupt software raid resync?

I want to interrupt a running resync operation on a debian squeeze software raid. (This is the regular scheduled compare resync. The raid array is still clean in such a case. Do not confuse this with ...
25
votes
1answer
4k views

When using software RAID and LVM on Linux, which IO scheduler and readahead settings are honored?

In the case of multiple layers (physical drives -> md -> dm -> lvm), how do the schedulers, readahead settings, and other disk settings interact? Imagine you have several disks (/dev/sda - /dev/sdd) ...
14
votes
4answers
26k views

Recommended disk/partition setup for a SQL Server

I'm looking for some advice regarding the best way to set up my disks/partitions for SQL Server. Here are some of my major concerns: How should the SQL files be seperated (data files, logs, temp)? ...
10
votes
2answers
8k 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 ...
10
votes
1answer
7k views

Easy to expand Linux software RAID 5 with XFS. Best practices?

I use my Ubuntu machine as a file server for Windows/Linux/Mac clients using a Samba share. I need it to be easily expandable by just adding more hard drives without having to move any data back and ...
25
votes
6answers
15k views

Is bit rot on hard drives a real problem? What can be done about it?

A friend is talking with me about the problem of bit rot - bits on drives randomly flipping, corrupting data. Incredibly rare, but with enough time it could be a problem, and it's impossible to detect....
15
votes
7answers
7k views

How many SMART sector reallocations indicate problems?

I have a NAS appliance that is just over a month old. It is configured to email me alerts generated from the hard drives' SMART data. After one day, one of the hard drives reported that a sector had ...
28
votes
9answers
9k views

To improve SQL performance, why not just put lots of RAM rather than having faster hard disks?

People keep telling me that in order to improve an SQL server's performance, buy the fastest hard disks possible with RAID 5, etc. So I was thinking, instead of spending all the money for RAID&...
24
votes
6answers
4k views

Scaling databases with cheap SSD hard drives

I hope that many of you are working with high traffic database-driven websites, and chances are that your main scalability issues are in the database. I noticed a couple of things lately: Most large ...
17
votes
4answers
1k views

Should you still spread a hard drive order over several vendors?

Once upon a time, I was taught that whenever I needed around six or more hard drives I should spread the order among at least two vendors, and three when the order gets up around 20 drives or more. ...
16
votes
4answers
10k views

Hardware RAID Controller Support for SSD TRIM

Do any hardware RAID controllers available today support TRIM? If not, do any manufacturers have target dates for supporting TRIM? Should I even care about TRIM for SSDs installed in performance-...
14
votes
21answers
5k views

When is RAID worth the trouble?

In our shop we're faithfully using RAID in all our workstations, probably just because that seems to be the way it ought to be done. I'm talking about workstations for scientific simulations, using ...
12
votes
11answers
2k views

Is RAID5 more robust than RAID1

I am about to replace an old hardware RAID5 array with a Linux software RAID1 array. I was talking to a friend and he claimed that RAID5 was more robust than RAID1. His claim was that with RAID5, on ...
12
votes
9answers
31k views

How many disks is too many in this RAID 5 configuration?

HP 2012i SAN, 7 disks in RAID 5 with 1 hot spare, took several days to expand the volume from 5 to 7 300GB SAS drives. Looking for suggestions about when and how I would determine that having 2 ...
11
votes
5answers
47k views

How to monitor the hard disk status behind Dell PERC H710 Raid Controller with CentOS 6?

I have a Dell server running CentOS 6 using PERC H710 Raid Controller card with Raid 5 setup and I want to monitor the hard disk failure/working status behind the Raid Controller. Then I should be ...
10
votes
7answers
4k views

Hot spare or extra parity drive in RAID array?

In a different question about configuring a RAID array, the author is building a RAID array with 8 drives. One answer suggests using 7 drives in RAID 5 with one left over as a hot spare. Since RAID 6 ...
9
votes
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 ...
8
votes
3answers
3k 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, ...
6
votes
2answers
15k views

Disk/RAID Monitoring for HP Proliant Servers and Ubuntu 12.04

How can I monitor the status of the hard disks and the RAIDs of an HP Proliant server using Ubuntu 12.04. In Ubuntu 10.04 I could use the cciss-vol-status to query the RAID status periodically but ...
19
votes
3answers
2k views

Can “enterprise” drives be safely replaced by near/midline in some situations?

When specifying servers, like (I would assume) many engineers who aren't experts in storage, I'll generally play it safe (and perhaps be a slave to marketing) by standardising on a minimum of 10k SAS ...
12
votes
7answers
38k views

What is a (raid-controller-) BBU for?

I am wondering what's the purpose of a BBU. My first understanding was, that it enables the cache to write the data to the disc during a power failure. But some specifications say that a BBU can hold ...
7
votes
4answers
5k 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 ...
6
votes
5answers
40k views

RAID 6 vs RAID 10? Which would you choose

My choice would be RAID 6 for a file server since you can lose two drives and it does not matter which set of two can die. From what I understand with RAID 10 you can lose two drives but if they ...
5
votes
2answers
6k views

Where should my swap partition/s live when using software RAID1? Performance? LVM?

When I search around for example RAID1 installations, it seems that admins tend to place their swap partition under RAID1. To me, it is more intuitive to have two disks, each with a large partition ...
16
votes
12answers
9k views

Should a backup server use RAID?

I was asked to set up a new backup server using Symantec Backup Exec that stores to hard disk instead of tape, because the backup size is outgrowing tape capacity. I was wondering does it really ...
10
votes
3answers
10k views

Is a large RAID-Z array just as bad as a large RAID-5 array?

For a long time I've heard about how bad an idea a large (>5TB?) RAID-5 array is simply because there's a high risk for another drive to fail. Has RAID-Z1 managed to remedy this for an array of any ...
7
votes
1answer
5k 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, ...
6
votes
4answers
2k views

ZFS on top of Hardware Mirroring, or just mirror in ZFS?

I have an IBM x346 with dual 3.2Ghz Xeons and 2x36GB 15k SCSI disks. I'm running an entirely ZFS-based install of FreeBSD 8.1. I can configure the bios to mirror the two disks, and then put ZFS on ...
5
votes
3answers
2k views

How can I uprade my software RAID1 set of drives?

I've got two 600GB drives in a software RAID1 setup on a physical Debian server. I want to be able to upgrade the capacity of the server by cloning the drives to a matching pair of 2TB drives. I can ...
4
votes
0answers
7k views

How to recover an mdadm array on Synology NAS with drive in “E” state?

Synology has a customized version the md driver and mdadm toolsets that adds a 'DriveError' flag to the rdev->flags structure in the kernel. Net effect - if you are unfortunate enough to get a array ...
4
votes
2answers
4k views

Is it possible to use Linux as a Fibre Channel Raid Disk Box?

You probably all know the relatively simple RAID boxes exporting a bunch of SATA disks as one big drive via FC, SAS or iSCSI, like the HP StorageWorks MSA2000, Infortrends EonStore series or many ...
4
votes
4answers
3k views

Which RAID Level Should We Run For Virtual Machine Storage

We just ordered a server which we are going to use as storage for our virtual machine environment. Basically it will work as a block level storage device running iSCSI to each hypervisor. The server ...
3
votes
1answer
9k views

Proliant server will not accept new hard disks in RAID 1+0?

I have a HP ProLiant DL380 G5, I have two logical drives configured with RAID. I have one logical drive RAID 1+0 with two 72 gb 10k sas 1 port spare no 376597-001. I had one hard disk fail and ...
3
votes
4answers
8k views

Windows file server performance tuning

I seek your opinion and tips/suggestions in optimizing the performance of a new Windows file server I'm building. I've inherited a Dell NF500 storage server (basically Dell 2950 with Windows 2k3 ...
1
vote
3answers
647 views

Hard disk / SSDs - detection and handling of errors - is silent data corruption reliably prevented?

When an error occurs on a drive, is it correct to assume that it will always be detected and reported to the OS (if software RAID such as mdadm) or RAID controller (if hardware RAID) as a failed read (...
20
votes
8answers
34k views

RAID-5: Two disks failed simultaneously?

We have a Dell PowerEdge T410 server running CentOS, with a RAID-5 array containing 5 Seagate Barracuda 3 TB SATA disks. Yesterday the system crashed (I don't know how exactly and I don't have any ...
19
votes
3answers
6k views

RAID-6: better to replace two dead drives at the same time, or one at a time?

We have a 16-drive RAID-6 that has three problem drives. Two are already dead, and the third is giving SMART warnings. (Nevermind how it got in such a bad state.) Obviously we want to replace the ...
18
votes
6answers
1k views

Should I 'run in' one disk of a new RAID 1 pair to decrease the chance of a similar failure time?

I'm setting up a RAID1 array of two new 4TB hard drives. I heard somewhere previously, that making a RAID1 array of new identical hard drives bought at the same time, increased the chance that they ...
11
votes
8answers
33k views

Guidelines for the maximum number of disks in a RAID set?

In any of the RAID levels that use striping, increasing the number of physical disks usually increases performance, but also increase the chance of any one disk in the set failing. I have this idea ...
6
votes
9answers
9k views

RAID strategy - 8 1TB drives

I'm setting up a backup storage device- This machine has Windows Server 2008, on a separate boot drive. It has 8x 1TB drives, and uses a hardware RAID card. My question is, which RAID configuration ...
5
votes
5answers
1k views

Need help with recovering RAID array

To make a long story short, I am responsible for a media server that has two RAID arrays (/dev/md0 and /dev/md2). I still have a ton to learn about software RAID and LVM, etc. We had a drive fail in ...