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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.


13

It would help if you posted your my.cnf and whether you are using InnoDB or MyISAM tables and whether you are a read-heavy or write-heavy workload. Otherwise, we are just making guesses. Here are mine: First, I would look and make sure that your queries are properly indexed. High I/O on MySQL databases is either caused by extremely high concurrency, a ...


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.


9

On modern hardware RAID controllers, RAID metadata is written to the disks, so they are somewhat portable, with restrictions on drive ordering; they have to be moved together. However, this is the wrong way to handle backups. Intentionally failing (groups of) disks and forcing a degraded array is fraught and a bad approach to accomplishing offsite backup. ...


9

First of all: to those, who still believes in "RAID0 has no hot spare". It could have a manual spare, done by human, who understand RAID levels and mdadm. mdadm is software RAID, so it could do a lot of interesting things. Credits to Zoredache for the idea! So, the situation: you have RAID0 array of two disks you would like to replace one of them without ...


8

In the case of this implementation (the LSI SAS2208 controller), JBOD does not use on-board cache, single disk RAID0 uses on-board write-back cache. The ceph benchmark explains it in the test setup. The performance increase comes from caching not striping. Most RAID controllers allow you to setup single disk RAID0 or RAID1 as a way to support JBOD, this ...


7

To add to the answer and to answer the comment (which is a bit too long to answer in a comment) You can try thinking from the very big picture. Will reading from 2 disks be faster than 1? And the obvious answer is yes. If one disk is only capable of reading 100MBps, two disks naturally can read at 200MBps. And that's why the theoretical read speed of raid 0 ...


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 ...


5

Yes, this is possible. See: Can I convert a 1 disk RAID 0 to RAID 1? You're lucky that your striped array has worked until now. The process you'll go through is an "array transformation". Make sure your system has a battery-backed cache (BBWC) on the RAID controller. Add two more disks of equal or greater size than the existing disks. Install the HP ...


5

The key thing to remember is that data is distributed in chunks, not per bit or per byte. The chunk size (aka stripe size) varies based on implementation, and is often configurable. The chunk size is typically somewhere between 32KB - 2M. So for a single read request of a file smaller then a single chunk, only a single member of the array will need to be ...


4

Depending on what controller you use it may be utilizing your built in CPU, so the more disks you add the more CPU will be used when doing huge transfers. So your CPU might indeed be your bottleneck. Apart from that:


3

Based on what you've posted so far my guess is that your striped volume is almost certainly being hampered by slower drives (I see one 6Gb/sec link and 3 3Gb/sec links - I'm willing to bet the 3Gb/sec drives also have lower general operating specs. Like @MikeyB said run speed tests for each disk individually - this will confirm my theory (or send you ...


3

Assuming your SATA card has enough ports then you can add it outside the RAID. Oh and don't mix disk types in RAIDs - bad idea, bad ;)


3

If the device is there at /mnt/md0 or wherever then dd will work, to backup to a file use: dd if=/dev/md0 of=/tmp/raid1.img the output can be another device: dd if=/dev/md0 of=/dev/sdb


3

Basically you're going to be using the DISKPART command, but you're going to have to figure out the exact details yourself.


3

Are you paying for provisioned IOPS? If not, you'll be getting around 100 IOPS per EBS on average, which ties in with what you're seeing with 8 EBS volumes tied together. From here: Standard volumes offer storage for applications with moderate or bursty I/O requirements. Standard volumes deliver approximately 100 IOPS on average with a best effort ...


3

The problem is that with the first command you create a new logical drive - when finished you will have two LDs, each containing one disk. What you need to do instead is add the unassigned disk to the original RAID0 LD and then invoke the modify command. In other words: ctrl slot=0 ld=1 add drives=allunassigned And then: ctrl slot=0 ld=1 modify raid=1 ...


3

I couldn't find a way to make the server itself tell the Windows installer how to see the disk, but by talking to @joeqwerty in the comments I ended up following this course, which worked: Download the latest drivers from Dell: I did that from my product's support page, going on "Drivers & Downloads", category "Driver for OS Deployment". There was one ...


3

What can I do to attempt to recover the files? Stop what you are doing. Power off the server. Remove the hard drives and ship them off to a professional data recovery shop. Period, full stop. You haven't a clue how exactly it was configured before, and anything more you do to it will cause further issues. I've had an idea of reconfiguring the RAID ...


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 ...


2

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


2

So you have a redundant array of disks that started to die. And you want to migrate it to the raid level where the death of a single disk will be fatal for data. My opinion - it's some sort of complicated suicide.


2

It looks like that is a custom build server. I presume the perc 6/i is on the motherboard. Assuming you have an appropriate pci-e slot available, I would just add a SATA controller HBA (one which can operate in IT mode, not a "Raid" one), and connect it to the backplane. I like LSI controllers and have been using the 9207-8i - I'm doing SAS (however they ...


2

Bad block check must be done in the disk device itself, since you are using mdadm RAID you should stop the array and run checks on /dev/sda2 and /dev/sdb2. But before doing this, if you value your data I do recommend a backup, the possibility of losing the entire RAID-0 array exists.


2

You should check your raid controller to see what the status is of the hard drives. If your green on all you should then go into disk management and check to see if the disks show. If they are there but show as foreign or inactive you'll need to either import them back or set them to active.


2

You're not going to be able to do this online, because RAID-0 is completely incapable of handling failures, and the md system depends on failures to trigger rebuilds onto spare components. There is no way to say "can you please use this device instead of that device" without saying "that device has failed" -- which, of course, is going to give your RAID-0 ...


2

There are a variety of tools that you can use. dd is probably as good as many. Clonezilla is a good tool, there are more on this wikipedia page too.


2

Most decently modern raid controllers won't care what physical slots the drives are in; the RAID config is stored on the drives themselves. What you'll want to do is to insert one pair into one of the systems, and boot into the RAID config tool with a key combination at boot. If the RAID cards in those Dells are the standard PERC cards, they'll either ...


2

First, many hardware RAID solutions (and all software RAID I know about) will let you add a single disk beside an existing set. You can think of a single disk as a one disk RAID0. Whether or not you can add a disk to a RAID0 set depends on the RAID implementation. An individual hardware RAID card may not let you do it, some might. As for mixing and ...



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