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6

The Apple provided Disk Utility (and diskutil shell command) will allow you full RAID control over internal and external drives. You do have to erase the drives to add the RAID capability, but then you can join those drives into RAID. That is the only potential drawback to implementing RAID storage on the Mac. Drive spanning, JBOD, striping and mirroring ...


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The previous answer I gave here was wrong (as is bmike's answer). The previous answer I gave was that if you have this as a problem, a workaround is to create an encrypted disk image that covers the entire AppleRaid set. This works, in theory, but is so horribly slow (like more than 10x as slow as the raw disk access) that it is basically unusable, which ...


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I was unable to find how to rebuild the RAID from disk utility after a couple of hours of research. However, I managed to do it from the command line. sudo diskutil list // to get a list of disks. Note the disk number of your new disk (e.g. disk4) sudo diskutil appleraid list // note the uuid of the raid in question sudo diskutil appleraid add member disk4 ...


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Yes, RAID 0 is faster than using the drives independently of each other. Whether or not its noticeably faster depends on what kind of application you're looking at. Some setups benefit hugely from a RAID 0 setup, while for others, its pretty marginal. There's also the convenience of everything being treated like one big drive. I will however say that ...


3

Do you have the following files? /System/Libraries/Extensions/HighPointIOP.kext /System/Libraries/Extensions/HighPointRR.kext If so, copy both of them to your desktop, then: Open those kexts and edit the Info.plist. Change all the 'External' references to 'Internal' Copy the modified kexts back to '/System/Libraries/Extensions/' from your desktop. ...


3

In a RAID 0 set established by Disk Utility you, of course, have zero redundancy. The moment one of the drives is lost from the set the entire set becomes useless and you have a volume failure. If (and only if) no attempt was made by anything to write to the volume while the physical drive wasn't there you might be lucky and it will be OK but otherwise you ...


3

In the end I went with the most expensive but also the fastest option: #1 which was the Mercury Accelsior PCIe based SSD hardware RAID array (RAID 0 by default which I will keep) in a Mercury Helios Thunderbolt PCIe chassis. The main reason was because it was the only one that mentioned it was bootable (and made a big deal out of that fact). I paid $799 ...


3

My guess would be that Apple prefers to have one drive handle only write processes as a backup and read/write from whichever one it considers the main drive. As to why this is, I have absolutely no clue. Seems kind of like a big oversight on their part. I've always kind of gotten the feeling that software RAID is pretty low on Apple's priority list.


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Disk Utility will only support RAID 1 and 0 using software raid. If you have the RAID Card for the Mac Pro, you can configure RAID 5. I've never actually used or configured one of these in the wild so I can't give you exact specifics on using it.


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I think you should be fine. I upgraded to Lion on a Mac Pro that has a RAID 0. While the OS is installed to an SSD, not RAID, Lion still detected the RAID just fine. That's obviously a different scenario than what you have, but as the software RAID is handled at a higher level than the OS, I think you should be fine. Obviously, have a backup ready to go ...


2

Both use the same data structure to create a volume within a volume. One creates a wrapper and the data that is on the disk is scrambled / mapped through a cryptographic function so that the same data written to two different blocks ends up physically different on the drive. That's FileVault 2. The other creates a wrapper and the data on the disk is either ...


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For redundancy and performance Apple steers you towards RAID 10. I built a 4 disk array by doing a mirrored pair of striped disks which I then converted to a core storage volume to facilitate easier expansion later and FileVault. I can watch data be written to both stripes with iostat but when I read, presumably this is abstracted by cs, as I see zero bytes ...


2

First let's clarify one thing: RAID is not the same as backup. Building a RAID array out of several (presumably USB) external drives would have many drawbacks. See this question I asked a while back for the explanation. I suspect what you really want is passive and seamless disk/data backup in which case OS X's built-in Time Machine works great. And if you ...


2

This can be done from the Disk Utility app or from the diskutil command line. Be warned that you should definitely make a backup before doing anything. I had an issue where the diskutil appleraid enable mirror disk1s2 command I ran wrapped the volume in a RAID set but the partition is now called Apple_RAID_Offline and no longer accessible. Ironically ...


2

You're thinking of RAID-1 in the wrong way. RAID-1 is not an architecture intended to happily use a single surviving drive within a raid-1 group, and work out mirroring content later. Ultimately it will do that, but that is considered a recovery operation from a failed state, and it will destructively overwrite the mirror drive after replacement. In RAID-1, ...


2

Firstly, RAID shouldn't include your backups. Something catastrophic hitting one, will hit the other. Eg. fire, burglary, etc. Ideally, you want to keep one set off site. Using the 2 disks you can keep one at a friends, and sync the up periodically. There are tools that allow you to do this. Alternatively, something like BackBlaze, Amazon Glacier, will give ...


2

Yes - Apple's software RAID works so that once all the drives are present (or in the case of RAID mirroring - enough drives to ensure one copy of the data is present), you can then mount the RAID volume. Unless you used a third party RAID driver in software or hardware, just getting the drives mounted should work.


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My experience is that TimeMachine does not cross the "per-machine" boundary when deleting old backups. We have a disk attached to an AirportExtreme AC and which is the target for four Macs. These machines have significant differences in the size of their backups. One of them in particular is an old Mini running 10.6.8 that does not see much activity other ...


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They are correct, and depending on who you talk to it is also sometimes called RAID 10 http://en.wikipedia.org/wiki/Nested_RAID_levels#RAID_1.2B0 And a Mirror of Stripes can often give you the speed advantages of a RAID 0 with the redundancy of a RAID 1. But RAID 5 and 10 (I believe) require 3rd party RAID software.


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Easy, the Disk Utility program on OS X allows creation of software RAID. Open Disk Utility from spotlight or /Applications/Utilities Type "Create RAID" into the help menu search term Go to the article and follow the steps for Create a mirrored RAID set This does involve erasing all drives, so you'll want to be sure everything is backed up elsewhere ...


1

As the saying goes: "The difference between RAID 1 and RAID 0 is that the zero stands for how many files you're going to have after a hard disk failure." Putting your 320 GB hard drive and your 120 GB SSD will allow you to share the space in between the two drives, but the risk in doing so is that you may have a failure at some point that makes your data ...


1

In general, Disk Utility forces you to erase a drive to turn on or off the RAID wrapper it places on the actual data. If you set up a mirrored set (RAID 1) you still have access to the data and could just ignore the RAID wrapper since it allows you to add more drives as mirrors in the future, but doesn't force you to do so and you can keep using it as a ...


1

So you currently have Disk1 + Disk2 = RAID Set1(striped) You want to know if you can RAID Set1 + Disk3 + Disk4 = RAID Set(striped). Disk Utility doesn't allows this. You can however have Disk3 + Disk4 = RAID Set2(striped) and then use a symbolic link or mounting to move the set to a location that is convenient for you. You would think that you could Disk1 ...


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You can setup a RAID 1 mirror over FireWire and connect the internal/external drives. However, I wouldn't recommend it. First, you'll need the same size drives to do the mirror. Second, the speed of both drives will be limited by the type of connection to the external drive, so if its USB, the computer will run at USB speeds. If you are just using this iMac ...


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In this situation, I recommend using disk utility to partition the larger drive such that one partition matches the size of the smaller drive. Then setup the partitions of the same size as a RAID1. You will end up with a mirrored partition of 1.5TB and another un-mirrored partition of 0.5TB based on your first example. Same thing will work for a 2TB + 3TB ...


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A mirrored RAID would operate only as fast as the slowest drive in the setup. In this case, unless you are using thunderbolt I imagine the performance would be awful. Another reason not to do a mirror with an external drive (if Disk Utility would even let you) is it'd be too easy have the mirror fail for a number of reasons. I would use Time Machine to ...


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Well you already have a pretty optimal setup. Having the two disks in RAID-0 as your boot drive gives you the greatest possible performance. Just be sure to keep a good backup, since if either disk fails you lose the whole array. Superduper! is great since it makes a bootable backup for you, unlike Time Machine. I highly recommend it. Otherwise you're good ...


1

Enabling a RAID is destructive to the existing data using disk utility and native OS X tools. You will need to have a temporary copy of the data to re-load it onto the new RAID volume. I know several people that always set up their externals to be in a RAID so they can always mirror up existing drives after the fact to duplicate, snapshot or extend/stripe ...



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