RAID, an acronym originally for Redundant Array of Inexpensive Disks (today usually interpreted as referred to as Redundant Array of Independent Disks), is a technology that provides increased storage performance and reliability through redundancy by spreading data across multiple disks using various algorithms (RAID-levels). RAID can be implemented in hardware storage controllers, or in software, usually as operating system/kernel features.
Questions tagged [raid]
3655 questions
33
votes
6 answers
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. In addition, there is a small yellow exclamation…
tputkonen
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5 answers
How do I differentiate "fake RAID" from real RAID?
The Ubuntu wiki page on FakeRaid says the following:
[A] number of hardware products ...
claim to be IDE or SATA RAID
controllers... Virtually none of these
are true hardware RAID controllers.
Instead, they are simply multi-channel
disk…
cdleary
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Can we mount multiple disks as one directory?
Is there a way to mount the different disks as one directory?
Assuming I have some disks with ext4 partitions:
/dev/sda1 1Tb mounted as /store1
/dev/sda2 2Tb mounted as /store2
/dev/sdb1 2Tb mounted as /store3
/dev/sdb2 2Tb mounted as /store4
I…
Arman
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31
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3 answers
Should I defrag my RAID volumes?
It seems to me that since RAID volumes are logical (as opposed to physical), the layout that the OS believes they have might not correspond to the actual phsyical layout.
So does defrag make sense for RAID?
Aidan Ryan
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31
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9 answers
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 5 and super-duper fast hard disks (which isn't cheap by…
user1034912
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30
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7 answers
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 able to use a bash script to monitor the hard disk…
Xianlin
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30
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7 answers
What are the performance differences between Raid 0,1,5,6,10
I have heard/read different performance stories on the various raid flavors. I am curious what the agreed upon best answer is.
James Moore
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29
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9 answers
Consumer (or prosumer) SSD's vs. fast HDD in a server environment
What are the pro's and con's of consumer SSDs vs. fast 10-15k spinning drives in a server environment? We cannot use enterprise SSDs in our case as they are prohibitively expensive. Here's some notes about our particular use case:
Hypervisor with…
David Budiac
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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) all part of a software RAID device (/dev/md0)…
andrew311
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28
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5 answers
What is the difference between a HBA card and a RAID card?
I thought I knew the difference between HBA and RAID.
In my mind, HBA is offloading from the main motherboard/CPU and is simply JBOD... usually has an external SAS ports, whilst a RAID card does the same job as HBA but adds all the nice RAID levels…
William Hilsum
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28
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5 answers
Do I need to RAID Fusion-io cards?
Can I run reliably with a single Fusion-io card installed in a server, or do I need to deploy two cards in a software RAID setup?
Fusion-io isn't very clear (almost misleading) on the topic when reviewing their marketing materials Given the cost of…
ewwhite
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27
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4 answers
If a RAID5 system experiences a URE during rebuild, is all the data lost?
I understand the argument regarding larger drives' increased likelihood of experiencing a URE during a rebuild, however I'm not sure what the actual implications are for this. This answer says that the entire rebuild fails, but does this mean that…
mboratko
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Can I detect hardware RAID information from inside Linux?
When I'm inside of Linux, I can get the following information from lsblk (irrelevant drives removed from output):
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 298G 0 disk
sdb 8:16 0 2.7T 0 disk
When I manually pull the…
IQAndreas
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3 answers
Is there a difference between RAID 10 (1+0) and RAID 01 (0+1)?
I've seen both of these listed, both being striped and mirrored across multiple drives, but is the a difference between them that I'm not picking up on?
notnot
25
votes
2 answers
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 motherboard which has a connection for a SFF-8087 to 4x…
Damainman
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