Re: Software RAID Question in All Things Unix http://www.dslreports.com/forum/r21176701 en Wed, 11 Nov 2009 03:42:54 EDT Wed, 11 Nov 2009 03:42:54 EDT Re: Software RAID Question http://www.dslreports.com/forum/remark,21246681 fcisler : 3ware and Areca cards are well supported.

I can only vouch for 3ware cards, as i've used the 9550 and 9650 series myself with great success. Native support (6.0+). When I started (5.9) you had to manually compile support - what a PITA installing. AFAIK, it's now native and no drivers needed. It has support for the 3dm tool (web based config) and also a daemon that checks health and status.

I've also gotten a SATA to eSATA bracket and used a eSATA HD for backups before....log into the 3dm admin, build a single disk array and mount it....umount and destroy single disk array, unplug. Blazing fast (versus USB) and easy.

I have a 9550 8 port at home. Currently 4x 320gb R5. FAST as all hell! I have 8x 1.5TB sitting in the box waiting...

Quite expensive. When I get the 9550 it was over $500. The 9650 was not out at the time. The 9550 is PCI-X. I had to search for a board I liked with PCI-X (64 bit/133Mhz). Now with the 9650 series it's PCI-E, and you have a much larger choice of boards. Next server I build will be using a 12 port 9650. That's when I pass the ~12tb mark, though....]]> http://www.dslreports.com/forum/remark,21246681 Fri, 10 Oct 2008 14:45:35 EDT Re: Software RAID Question http://www.dslreports.com/forum/remark,21241747 bmeeks8 :
said by MaxCras See Profile :

Now I am looking into other operating systems (FreeBSD and CentOS) will my software RAID transfer over to either of those operating systems seamlessly?
It should. That's the beauty of Linux software RAID- you are not tied to specific hardware drivers.]]> http://www.dslreports.com/forum/remark,21241747 Thu, 09 Oct 2008 16:49:10 EDT Re: Software RAID Question http://www.dslreports.com/forum/remark,21241525 MaxCras : I'm going to bring this one back from the dead.

Now I am looking into other operating systems (FreeBSD and CentOS) will my software RAID transfer over to either of those operating systems seamlessly? ]]> http://www.dslreports.com/forum/remark,21241525 Thu, 09 Oct 2008 16:09:52 EDT Re: Software RAID Question http://www.dslreports.com/forum/remark,21207893 MaxCras : After all of my worrying and question asking, it turned out that I had to do NOTHING to make it work. lol

Well, I did have to screw around with the settings in the OpenSuSE 11 installer to make sure it did not decide to format and re-partition my RAID array, but other than that, when the system booted I typed

mount /dev/md0 /storage

and it mounted without as much as a peep!]]> http://www.dslreports.com/forum/remark,21207893 Thu, 02 Oct 2008 23:04:41 EDT Re: Software RAID Question http://www.dslreports.com/forum/remark,21183020 MaxCras : It's still a year or so off though ]]> http://www.dslreports.com/forum/remark,21183020 Sun, 28 Sep 2008 18:39:08 EDT Re: Software RAID Question http://www.dslreports.com/forum/remark,21182921 Brano : Why don't you give SW raid a try? It's very easy to setup and once running it's pretty much zero maintenance.
Just install the mdadm package and read manual or some HOW-TOs on internet.
I'm running openSUSE and it has great GUI to create RAID devices am sure other distros have similar features.

Mdadm is a SW package to manage the kernel raid.
»neil.brown.name/blog/mdadm
»en.wikipedia.org/wiki/Mdadm]]> http://www.dslreports.com/forum/remark,21182921 Sun, 28 Sep 2008 18:17:23 EDT Re: Software RAID Question http://www.dslreports.com/forum/remark,21181615 MaxCras : Oh yeah, a hardware RAID card is at least a year off, and by then the server itself will most likely be upgraded, and who knows what type of RAID they may include in motherboards]]> http://www.dslreports.com/forum/remark,21181615 Sun, 28 Sep 2008 12:06:58 EDT Re: Software RAID Question http://www.dslreports.com/forum/remark,21181468 bmeeks8 : I agree wholeheartedly that software RAID is a great choice for any home server since these are generally never highly loaded. While there certainly is a tiny performance hint for RAID writes in both of the popular RAID 1 and RAID 5 schemes, it is truly tiny unless the server is seriously underpowered.

As pointed out by Brano's post, the great benefit of software RAID is more or less complete immunization from hardware failure with obscelence. I've seen several posts over the last couple of years in various groups where users had a failed RAID card, could not find a replacement because the vendor was out of business, and thus their data was not recoverable. Same thing can happen if you want to move to a new version of OS and then you find out your hardware RAID card is not supported (or maybe key features like the management software for it is not supported under the new OS). With Linux software RAID, you are pretty well insulated from these kinds of issues.]]> http://www.dslreports.com/forum/remark,21181468 Sun, 28 Sep 2008 11:24:52 EDT Re: Software RAID Question http://www.dslreports.com/forum/remark,21181213 MaxCras : The server acts as a:
•DHCP Server
•DNS Server
•Web Server(Apache, PHP, MySql)
•CS:S Dedicated Server
•Twonky Media Server(Streaming to X360, Wii and PS3)
•Samba

The webserver is for internal use only, but at any point in time Twonky and Samba could be serving 6+ clients with anywhere from 192kbps MP3 files up to 720p video files.]]> http://www.dslreports.com/forum/remark,21181213 Sun, 28 Sep 2008 09:46:07 EDT Re: Software RAID Question http://www.dslreports.com/forum/remark,21180458 Brano : What are you running on that machine?

Having true raid may be overkill. Unless your CPU is most of the time over 80% or you're running some ERP DB having a pseudo raid or software (kernel) raid may just do the trick for you.

As an example, on my home server I'm running purely software (kernel) raid, two system disks are in raid1 and 4 data disks are in raid5. Granted I'm just running personal web, mail and some photo albums but the CPU is mostly close to zero and raid overhead on it is not measurable.

With HW raid you should also consider compatibility. Should your RAID card die you better have exactly same one on the shelf for replacement (or really use expensive brand name one).

Having said that, with good HW raid card you can't go wrong ;)]]> http://www.dslreports.com/forum/remark,21180458 Sun, 28 Sep 2008 00:16:52 EDT Re: Software RAID Question http://www.dslreports.com/forum/remark,21180407 MaxCras : As stated a few times in this post I am well aware about RAID 0 and it's lack of protection (look at the 8th post)

I have not decided on a particular RAID card yet, but I am also well aware of the difference between RAID cards and RAID cards

Now if anyone has any good true SATA RAID cards that they have worked with, I would love to get some good personal reviews. :D]]> http://www.dslreports.com/forum/remark,21180407 Sun, 28 Sep 2008 00:00:30 EDT Re: Software RAID Question http://www.dslreports.com/forum/remark,21179767 Brano :
said by MaxCras See Profile :

The processing cost of the parity calculations would be absorbed by the controller card...
Well, that really depends on what card you have.
There are RAID controllers and there are RAID controllers ;)

Some of them are true raid (usually $300 and higher) and pseudo-raid which is all the cheaper stuff. To be exactly sure you have to check specs of your card. I'd say 100% of the on-board raid on motherboards in the $100 range are the latter.

The difference is that true raid controller does all the calculations on the controller card.

The pseudo raid controller is using the main CPU for the calculations. Having said that the RAID 5 parity speed degradation is typically noticeable only in degraded array mode when one disk is failed or in reconstruction mode.
Under normal write operations it's hardly noticeable.

For the OP. Raid 0 does not give you protection, only possible speed increase.]]> http://www.dslreports.com/forum/remark,21179767 Sat, 27 Sep 2008 21:11:57 EDT Re: Software RAID Question http://www.dslreports.com/forum/remark,21178606 anon : Thank you for the detailed explanation, I hope my initial post didn't come across as accusatory. Your reply does make sense, I was trying to verify that I myself wasn't suffering from antiquated "wrong thinking" :) ]]> http://www.dslreports.com/forum/remark,21178606 Sat, 27 Sep 2008 15:44:25 EDT Re: Software RAID Question http://www.dslreports.com/forum/remark,21177667 MaxCras : Sorry, I should have been a little more clear on what I meant about faster speeds and RAID 5. I was planning on adding 2 more 1TB drives into the array, and use a SATA RAID controller card to handle the array as opposed to the controller on board. Since most of my drive operations are read operations there would be a increase (if only slight) in speed due to the fact that the data is striped across 3 drives as opposed to two. The processing cost of the parity calculations would be absorbed by the controller card, so the write speed difference would come out to a wash.

Granted this is only comparing the differences in performance between my current software RAID 0 setup and my future RAID 5 setup.]]> http://www.dslreports.com/forum/remark,21177667 Sat, 27 Sep 2008 11:33:52 EDT Re: Software RAID Question http://www.dslreports.com/forum/remark,21177325 JohnInSJ : I would think you'd have a clear win on read speeds. Write should still be a win.

I use a raid0 for speed, and it's clearly faster at both read and write (and yes, its for disposable content) ]]> http://www.dslreports.com/forum/remark,21177325 Sat, 27 Sep 2008 09:56:23 EDT Re: Software RAID Question http://www.dslreports.com/forum/remark,21176734 anon : Educate me with regard to RAID5 and faster speeds if you would, I've always been lead to believe (and see first hand) the parity calculations kill any speed increases as a result of introducing an additiona spindle.]]> http://www.dslreports.com/forum/remark,21176734 Sat, 27 Sep 2008 01:16:38 EDT Re: Software RAID Question http://www.dslreports.com/forum/remark,21176701 MaxCras : Yeah, I was thinking about moving up to RAID5, mainly because there is the potential of slightly faster speeds, but I only had the cash to get the 2x 1TB drives. They are the WD Green Power series, so I think that the partial spindowns (7200 down to 5400) might increase the overall life of the drive too.]]> http://www.dslreports.com/forum/remark,21176701 Sat, 27 Sep 2008 01:01:26 EDT Re: Software RAID Question http://www.dslreports.com/forum/remark,21174099 bmeeks8 : OK. I figured you knew, but just thought I'd ask. I have a similar collection of data but opted to use software RAID 5 to hold it. I have a 1.4 TB RAID 5 array in a Fedora Core box with six 320 GB SATA II drives.]]> http://www.dslreports.com/forum/remark,21174099 Fri, 26 Sep 2008 16:29:13 EDT Re: Software RAID Question http://www.dslreports.com/forum/remark,21168722 MaxCras : I am aware of the potential data loss if one of my drives were to die. I used RAID 0 as opposed to RAID 1 because speed and storage space ranked much higher than redundancy.

All of my important files are backed up both on tape and stored in my lock box as well as to a server off site, which amounts to about 4gb of data.

The remainder of the data is Music, videos, CD images, ect... Data that I value greatly, but if were lost would not be the end of the world, I would just be rather pissed because it would be a lot of stuff to rip / download again.

If I really wanted to, I could backup all of the data to my companies server I just finished (16TB RAID 5 array) but that would take forever over my 8/1 net connection. :D]]> http://www.dslreports.com/forum/remark,21168722 Thu, 25 Sep 2008 17:49:32 EDT Re: Software RAID Question http://www.dslreports.com/forum/remark,21168581 bmeeks8 : I assume you do realize that with RAID0 if you lose one of those drives your data is gone. If it were RAID1 you would be safer. I point this out because you seem worried about losing the 1 TB of data with the upgrade.

The upgrade is not your only source of risk for this data if it is valuable to you.]]> http://www.dslreports.com/forum/remark,21168581 Thu, 25 Sep 2008 17:22:19 EDT Re: Software RAID Question http://www.dslreports.com/forum/remark,21167280 pablo2525 : I need to do the same on one of my machine's. It's running openSUSE 10.0 with a custom kernel ... but it's very outdated.

The nice thing is you can pop the new drive in, start the install and things look sketchy, stop the install before anything gets started and pop the old drive back in.

Edit: I do believe you want to keep the RAID device up and running.]]> http://www.dslreports.com/forum/remark,21167280 Thu, 25 Sep 2008 13:47:17 EDT Re: Software RAID Question http://www.dslreports.com/forum/remark,21167262 MaxCras : Cool, after I back a few things up (DHCPD, DNS, ect.. server config files) looks like I will finally take the plunge and update this damn server!]]> http://www.dslreports.com/forum/remark,21167262 Thu, 25 Sep 2008 13:42:32 EDT Re: Software RAID Question http://www.dslreports.com/forum/remark,21167230 pablo2525 : Hi,

Yes, the RAID device should work fine by simply adding the entries back in /etc/fstab. However, I don't know if there are any RAID daemons which are running on the machine. Are there?

If so, you'll want them installed and setup as part of the installation.

There really should be no danger leaving the current RAID devices on and it may be preferable.
--
pablo
openSUSE 11.0;KDE
ISP: TekSavvy DSL; backhauled via a 6KM wireless link]]> http://www.dslreports.com/forum/remark,21167230 Thu, 25 Sep 2008 13:37:15 EDT Re: Software RAID Question http://www.dslreports.com/forum/remark,21167212 MaxCras : Well, to be safe I will keep the RAID array powered down while doing the system install. If I had a way to back up the contents of the raid array (pushing 1TB now) it would all be a different story and I would be willing to chance things a bit more.

But, if I understand you correctly, the only thing I need to insure that the array will work are it's lines in the FSTAB file?]]> http://www.dslreports.com/forum/remark,21167212 Thu, 25 Sep 2008 13:33:06 EDT Re: Software RAID Question http://www.dslreports.com/forum/remark,21167132 pablo2525 : I'd do 2) too ... all you need to do is plop the new drive and boot off the installation DVD. During setup, you _should_ see the RAID device and you should be able to mount it ... if not, you can mount it after the fact. You can preserve your current /etc/fstab entry and manually edit the entry back.]]> http://www.dslreports.com/forum/remark,21167132 Thu, 25 Sep 2008 13:20:38 EDT Software RAID Question http://www.dslreports.com/forum/remark,21166815 MaxCras : I have a problem. I am not sure if it is a big problem or a small problem, but one none the less.

I am currently running OpenSuSE 10.3 on my file server, and have a Software RAID 0 array across 2 1TB WD SATA drives.

My problem is that my main OS drive (ancient 30gb IBM drive) is starting to act up. I want to replace that drive with a newer SATA drive I have and upgrade the system to OpenSuSE 11.

I am stuck at what exactly to do though. I have two (well, 2.5) ideas, but I'm not sure which one would work, if either.

1)Boot off of a live CD, copy the entire root partition to the new drive, update the FSTAB on the new drive to point to the SATA drive for the root as opposed to the old IDE drive, and then rebuild grub on the new drive. Then boot off of the OpenSuse 11 DVD and do a update install. The update install should technically rebuild the boot loader so I should be fine if I omit that step.

1.5)Upgrade the current system drive to OpenSuSE 11, then boot off of a live cd, copy the root over to the new drive and then rebuild grub.

2)Somehow backup the RAID config from the current system, perform a clean system install on the new drive, and then transplant the RAID config to the new install.

I would prefer to do #2 mainly because I want to start from a clean slate, but I am not exactly sure how to go about it. ]]> http://www.dslreports.com/forum/remark,21166815 Thu, 25 Sep 2008 12:28:04 EDT