Software RAID (mdadm) and you!

[Automata]

If I was stuck with RAID 5, I'd do a hotspare. With RAID 6, I wouldn't do a hotspare as you have two other drives before complete array failure.

Not to mention, my RAID card is absolutely deafening when a drive fails.

 

[cw823]

Yeah I just like the idea of the hotspare, that it will instantly begin rebuilding and not wait on any sort of input from me. Then I think, what do I need just under 15tb of storage for? Even now I'm only at just over 9tb of data.

I'll probably keep adding a drive here and there, and when I get a new drive I'll just grow the array onto the "old" hotspare, and install the new drive as a hotspare.

2tb 7K3000 open box from the egg for $74 today, factory warranty!

 

[Automata]

Media eats up a lot of space. I'm sure that you have Bluray/DVDs and music. I need to re-rip all my DVDs after I learn to not be a complete idiot at it and eventually move to Bluray rips. My "Lossless Music" folder (FLAC media) is 142.4 GiB. In addition to that, backups take a lot of space; at least on my level. My server keeps a copy of "My Documents", my WoW folder, my Steam folder and a few various others. That stacks up to quite a bit of space.

I just need to get off my lazy butt and start ripping media.

 

[cw823]

Probably 60% of my media is mkv. As it stands right now I do have alot of DVD quality movies, older stuff.

MediaCenterMaster tells me I have the following in my collection:
1560 Movies
165 TV Shows
134 Kids Movies

I have alot of old stuff too, like 1931 Frankenstein.

I would like to use WHS for workstation backups, but I see no other features I'd use.

I have alot of music too, although it's wildly unsorted. I have a 17" touchscreen from work that I want to turn into the front end of a jukebox, but haven't even started that project yet.

 

[Automata]

Now that you got all that space, we need to get you on a real operating system.

 

[cw823]

Now that you got all that space, we need to get you on a real operating system.

I tried installing Windows 95 but it had alot of drivers I couldn't find.

 

[Automata]

I tried installing Windows 95 but it had alot of drivers I couldn't find.

That would actually be a fun project. I got a copy of 98 that someone gave me.

That is, until it BSOD constantly like the POC it was!

 

[cw823]

I stumbled across 7 Win2K OEM CDs the other day, always hang on to stuff like that even though I'll never need it.

I think for my RAID6, if I had it to do again, I'd probably do RAID5 + at least one hotspare. In theory it's sort of the same thing, but choosing between being able to lose 2 disks, and having to replace/rebuild, or being able to lose 1 disk, but have one available to rebuild the array if one fails, I'd prefer the latter. My current solution is great but requires input if a drive or two fails, as opposed to hotspares where it just takes off rebuilding.

But, the more hotspares I have, the smaller my array appears to be.

 

[cw823]

Well, even though I didn't want to, I AM now experimenting with downsizing the size and number of devices of a raid array. Trying it via VM right now, not as difficult as I though although you do need a 3.1.x variant of mdadm

 

[HankB]

Well, even though I didn't want to, I AM now experimenting with downsizing the size and number of devices of a raid array. Trying it via VM right now, not as difficult as I though although you do need a 3.1.x variant of mdadm

Good luck!

I'm really happy that with a pair of 2TB drives in RAID1, I can remove one drive form the raid, mess with it, create a new degraded RAID1, copy data over and then fiddle with the other drive. Plus I have a 1.5TB USB drive that still holds the RAID contents. But it is amazing what Linux RAID can do.

 

[cw823]

Since my brand new RMA drive from Hitachi is DOA, I don't have enough drives to complete copying everything off of my old ubuntu array onto my new areca array. I need one drive from my old array, so here's the plan. It's currently a RAID6 with 8 drives, both parity drives are removed and added to my primary array. I still have 1.2tb of data that needs to be copied, but my new array (5x2tb in a raid5) is full. Full. So I'm planning to resize the RAID6 to a RAID5 of 6 drives, then remove the parity drive. All the data that is on there that I would like to copy can be recreated, so not a big deal.

I have not done this yet, but here is the basic idea. Have done it in a VM, lol. I would like to switch to fewer devices and raid5, that may be the kicker here.


http://www.issociate.de/board/goto/2056451/RAID5_Shrinking_array-size_nearly_killed_the_system.html

 

[cw823]

My raid device was an 8 drive RAID6. Here is how I resized my array:

First of all, I've already removed 2 drives, so it was a RAID6 missing two drives.

THis is /dev/md1 which consists of drives /dev/sdb /dev/sdc /dev/sdd /dev/sde /dev/sd

umount /dev/md1
e2fsck -f /dev/md1
resize2fs /dev/md1 5800G
mdadm --grow /dev/md1 --array-size 6400000000
mdadm -G -n 6 --backup-file=/mnt/tmp/file1.bak /dev/md1
resize2fs /dev/md1
e2fsck -f /dev/md1

I then edited /etc/mdadm/mdadm.conf to reflect only 6 drives instead of 8.

mdadm /dev/md1 --fail /dev/sdg
mdadm /dev/md1 --remove /dev/sdg

Holy crap it worked.

There's your answer thideras, I would guess you could even change raid level if you wanted to.

 

[cw823]

Other specific testing anyone would prefer me to attempt?

 

[Automata]

Can't think of anything other than a drive going unresponsive, but that is difficult to test. From what I've recently read, it will wait indefinitely for a drive to come back.

 

[cw823]

So it's not failed, just defunct? I agree it's a tough one to recreate, hmmm.

 

[Automata]

Such as TLER and similar features.

 

[cw823]

Such as TLER and similar features.

You buy the drives and I'll do the testing.

 

[polarbeardav]

Sorry to dig up old threads, but has any progress been made on this? Just curious.

 

[Automata]

Unfortunately, this is not an active project. Did you have a question? We do have a few members here that use software RAID normally.

 

[polarbeardav]

Basically which is the best software raid solution to use. mdadm seems promising but I'm not sold.