stupid RAID1 questions

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graysky

Gawd
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May 6, 2007
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I've never considered using a RAID1 setup before, but I am now and have a few basic questions.

Q1: If I use a pair of matched drives, can I make two partitions, one FAT32 and one NTFS (install the O/S on say a 20 gig FAT32 partition and make the rest of the array a data partition)?

Q2: In the event of a drive failure, do I simply plug in another drive and some how use software to rebuild the array?

Q3: If I build the array using an Intel P35-based MB and then upgrade motherboards in the future to a totally new chipset (say in 2 years or so when Nehalem chips have saturated the market place), will the data in the RAID1 work on the new board with a new controller?
 
Yes you can make multiple partitions on a single array. The array itself will show up as a single drive from the OS's point of view. You can split it into as many partitions as your os supports.

If you have a bad hard drive you replace it and you will either have to tell it to rebuild via the raid controller or the software to manage it. Depending on how it is configured it may start the rebuild for you.

With a raid if you need to move it to another motherboard it may or may not read as a raid 1. It should however show up as 2 seperate drives with the data on each of them. Mind you moving to another controller will probability stop the os on it from working right.
 
@swatbat - okay, interesting... so if I break up the array (i.e. remove one of the two disks), and move it into a newer or older motherboard with a RAID controller, it should work then..?

What happens if I just plug it into a non-RAID motherboard? Is the filesystem 100 % usable just as if it were a natively partitioned/formatted without any traces of RAID?
 
graysky said:
@swatbat - okay, interesting... so if I break up the array (i.e. remove one of the two disks), and move it into a newer or older motherboard with a RAID controller, it should work then..?

What happens if I just plug it into a non-RAID motherboard? Is the filesystem 100 % usable just as if it were a natively partitioned/formatted without any traces of RAID?
Click to expand...

You will be able to read the data off it. If you move a windows install to another motherboard with a different chipset you will probability run into issues getting it to boot(raid or not).

As long as you are running standard raid 1 you should be able to "break" the array by plugging in one of the 2 drivers into something elce(another system, usb enclosure, etc) and read the system without issue. It is a nice feature of a raid 1.
 
@swatbat - okay, that's cool. I don't care about reading the O/S, my concern will be migrating the data partition from the array in a few years to a new system.

If what you said is true about breaking a RAID1, does it make sense to leave one of the two disks unplugged most of the time? In other words, once a week sync the data by booting with two drives, but most of the time operating with one of the two powered-up? Seems like that would be playing the odds to put more mileage on one of the two discs, right? As long as you're prepared to potentially lose the data between synchronizations, that should offer additional protection, no?
 
graysky said:
@swatbat - okay, that's cool. I don't care about reading the O/S, my concern will be migrating the data partition from the array in a few years to a new system.

If what you said is true about breaking a RAID1, does it make sense to leave one of the two disks unplugged most of the time? In other words, once a week sync the data by booting with two drives, but most of the time operating with one of the two powered-up? Seems like that would be playing the odds to put more mileage on one of the two discs, right? As long as you're prepared to potentially lose the data between synchronizations, that should offer additional protection, no?
Click to expand...

No. Raid is not a backup. It is an uptime tool. If you wanted to do the once a week thing your best bet would be a second hard drive and a backup software package.

Also remember the connectors used on hard drives are not designed to be plugged in time and time again. You doing it weekly will just increase the rate of failure on them. Even wtih hotswap trays on sata drives they just plug the back of the drive into a connector as all sata drives have the power and data in the same place. You would end up wearing out the data and power plugs on it over time. Unplugging it 10 times sure no issues. Doing it a few hundred on the other hand might cause some.
 
I'd just like to point out that pulling a single drive from a RAID1 array and mounting it somewhere else is NOT something you want to do to an array you plan to rebuild in the future. Merely mounting a partition often causes the data on it to be changed, even if it's just some kind of timestamp. Recovering from this could be extremely painful.
 
LstOfTheBrunnenG said:
I'd just like to point out that pulling a single drive from a RAID1 array and mounting it somewhere else is NOT something you want to do to an array you plan to rebuild in the future. Merely mounting a partition often causes the data on it to be changed, even if it's just some kind of timestamp. Recovering from this could be extremely painful.
Click to expand...

That is a valid point. If you are moving to a new system though it might not matter. In the case of using onboard arrays you never know.

Generaly you are only going to be breaking a a raid one and hooking it to another machine to do recovery work anyway. I've also broke them multiple times in the past where something screws up pretty big on a server or something running one and I want a point of refrence. I'll pull one of the drives and throw it aside and start working on the problem. That way if it gets wost I have an untouched drive. If I fix it and am happy I let the server overwrite the pulled drive with the new data. Most of the times if it comes down to this though I'm replacing the pulled drive with a new one and letting it rebuild to that. That way I have the untouched drive in case something got damged or what not. A 60 dollar sata drive or 300 dollar sas drive is just not worth the data that could be on it.
 
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