Hot answers tagged

35

You actually part answered this in your question. The lowest form of RAID is RAID 1. RAID 0 was added well after RAID was defined (can't find reference to a date for this though) The 0 in RAID 0 is used to signify that actually it isn't considered redundant. Think of it as more True/False where 0 is False.


12

RAID is just a name with a meaning that changed over time. The important part is that the underlying technology and mechanisms are the same for the RAID levels, so you use the same controller (or piece of software, e.g. mdraid) to achieve all RAID levels.


6

As others have suggested, RAID 0 could be taken as level 0 meaning zero redundancy. It is referred to as RAID even though there is no redundancy for two other reasons: It is usually defined and talked about in the same contexts, so the name stuck. The same can't be said for JBOD, but such arrangements don't tend to get described along with RAID levels ...


2

Because "not redundant" is a valid point on the scale of how redundant something is.


2

Normaly you talk about a RAID Level. So i you say a System is RAID-0 it does not mean it is 'redundant with type 0', it does only mean it is of 'RAID Level 0', witch means no raid at all.


2

mdadm(8) sez: The GROW mode is used for changing the size or shape of an active array. [...] Currently the supported changes include [...] convert between RAID1 and RAID5, between RAID5 and RAID6, between RAID0, RAID4, and RAID5, and between RAID0 and RAID10 (in the near-2 mode). So, going from RAID1 to RAID0 doesn't appear to be ...


1

Ohh and if the drive is shown as unconfigured good now. There is a trick to get your data back - just recreate RAID 0 with the same parameters as you had earlier and when it asks you to Initialize the array just say NO. It will create new config on a drive but won't wipe it. Hope it helps.


1

A software RAID1 needs to duplicate each data chunk, effectively transmitting it two times down the SB and SATA link. This means that sometime, due to bus congestion a significant IOPS decrease can be observed when using high performance storage drivers (in your case, SSDs). Try to increase the I/O queue length and/or to switch to deadline scheduler, as ...


1

I wouldn't say you're going to have an issue. Read/Write speeds can vary on a lot of things when it comes to individual desktop setups. Setting up a RAID-0 is usually only a good idea if you know for a fact that your hard drive is causing a bottleneck. RAID-0 can reduce or remove the hard drive bottleneck if your hard drive was having problems keeping up ...


1

Is it possible? Of course, but with a RAID0, you will only use the same size on the HDD as is the SSD, which will usually be smaller. Will it provide good performance? Obviously not, except in edge cases where you read/write only from a fast stripe on the SSD. The slow stripes will severely impact the performance of the whole array. On average, you might ...


1

RAID 0 shouldn't be used. There's enough information out there detailing RAID levels that I don't think you need to benchmark this. I hope this isn't a homework question. What are the different widely used RAID levels and when should I consider them?



Only top voted, non community-wiki answers of a minimum length are eligible