A type of RAID redundancy that includes parity data spread across a number of member disks
Questions tagged [raid-5]
223 questions
35
votes
5 answers
How does parity work on a RAID-5 array?
I'm looking to build a nice little RAID array for dedicated backups. I'd like to have about 2-4TB of space available, as I have this nasty little habit of digitizing everything. Thus, I need a lot of storage and a lot of redundancy in case of drive…
Naftuli Kay
- 9,791
34
votes
4 answers
How do I reactivate my MDADM RAID5 array?
I've just moved house which involved dismantling my server and re-connecting it. Since doing so, one of my MDADM RAID5 arrays is appearing as inactive:
root@mserver:/tmp# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4] [linear] [multipath]…
Jon Cage
- 2,627
33
votes
2 answers
Can I set up a RAID 5 with a bunch of drives of different sizes?
I currently have 3 1TB drives, a couple 500GB ones and some 750GB ones. Can I put them all in a RAID 5 configuration or do they need to be of same size?
nopcorn
- 16,982
21
votes
2 answers
How to calculate the final RAID size of a RAID 5 array?
What is the formula for working out the final RAID size of a RAID 5 array knowing the number of disk and the size of each disk?
GateKiller
- 457
19
votes
7 answers
Should I use "Raid 5 + spare" or "Raid 6"?
What is "Raid 5 + Spare" (excerpt from User Manual, Sect 4.17.2, P.54):
RAID5+Spare: RAID 5+Spare is a RAID 5 array in which one disk is
used as spare to rebuild the system as soon as a disk fails (Fig. 79).
At least four disks are required. If…
Trevor Boyd Smith
- 2,924
18
votes
3 answers
How to force mdadm to stop RAID5 array?
I have /dev/md127 RAID5 array that consisted of four drives. I managed to hot remove them from the array and currently /dev/md127 does not have any drives:
cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4]…
matt
- 748
15
votes
10 answers
Looking for an actual experience of RAID 5 2 drive failure?
I'm wondering if anyone has any personal experience of RAID 5 2 drive failure with large drives?
As I understand it, the theory is that with large 1-2TB drives, if one drive fails in the raid set, it needs to rebuild everything so is thus hitting…
Brian
- 358
9
votes
2 answers
RAID5 vs RAID4 purpose of floating parity
I still did not get why is RAID5 better than RAID4. I understand both computes parity bits that are used for recovering if some failure occurs, the only difference is in storing those parity bits. I have borrowed diagrams from here How does parity…
Wakan Tanka
- 769
8
votes
2 answers
Data Recovery from RAID5 disk - Promise Pegasus with Apple OSLion and Thunderbolt connection
I have a Promise Pegasus R6 - 12 TB RAID 5 disk for major storage purposes. One of the six 2TB hard disks were dead and the company provided me with a replacement. When the disk was inserted it installed itself as a separate partition and their…
8
votes
1 answer
Find files affected by bad blocks with md-raid5 and LVM
I've been doing a lot of research on this topic over the last few weeks - and I think I'm close to completing my recovery, as much as is possible at least. To make a long story short, I'll just describe the problem without filling in every tiny…
Rob
- 81
8
votes
3 answers
How does RAID5 work?
In a raid 5 setup, you get 4 TB of usable space out of 3 x 2 TB disks. How is that possible?
Simple minded as I am, I would think that you need 4TB to store your things, and use the remaining 2TB for recovery. But how can I recover 4TB out of only…
exolab
- 365
8
votes
3 answers
Practical RAID Performance?
I've always thought the following to be a general rule of thumb for RAID:
RAID 0: Best performance for READ and WRITE from stripping, greatest risk
RAID 1: Redundant, decent for READ (I believe it can read from different parts of a file from…
wag2639
- 7,244
8
votes
1 answer
RAID 5 Array: Probability of Failing to Rebuild Array
I have a Qnap ts463u-rp data storage array, which contains 4x4TB HDD.
my question here is, is it safe to configure 3x4TB as RAID 5?
because from what I understood, it's not recommend to configure 12TB storage with RAID 5, because of the…
M. Ahmed
- 81
6
votes
2 answers
Bad performance with Linux software RAID5 and LUKS encryption
I have set up a Linux software RAID5 on three hard drives and want to encrypt it with cryptsetup/LUKS. My tests showed that the encryption leads to a massive performance decrease that I cannot explain.
The RAID5 is able to write 187 MB/s [1] without…
Philipp Wendler
- 564
6
votes
3 answers
Hardware RAID - what happens if the motherboard or controller fails?
I want to set up a RAID 5 array in a machine that has an intel motherboard. It has built in raid (sata). My concern is what happens if the motherboard fails?
How can I take those hard drives and move them to a different machine - with a…
Scott Sz
- 1,943