Topic: raid questions

[vortex]

Hi,

I am trying software raid for the first time (SME 6.0.1) and was wondering about connecting the cdrom drive.

I have identical 80GB drives on IDE 1 (Master) & IDE 2 (Master). I also have the cdrom connected to IDE 2 as slave. Will this affect the raid stability / performance? Should I disconnect the cdrom after installation and only reconnect it when I need it?  

My other option is HW raid.

Has anyone had any experience with the "Adaptec Serial ATA RAID 1210SA" card? It claims support for RedHat Linux 7.3 but I am not sure if you just plug it in and it works or whether drivers modification to SME are required.

The "Adaptec ATA RAID 1200A" also seems in my price range but does not mention linux at all.

thanks

[pwgsc1]

Hey Vortec,

Here's my experience with raid as of two days ago.  I was at a clients office and he wanted confirmation that if one of the drives goes down that the other one would still run and have the data on it.

I didn't supply the hardware so I was a bit surprised when I opened the case and saw that the harddrives and connectors where different then what I'm use to. The ribbon cables I was use too where not there, instead, there where only two small red cables connecting the harddrives. I've never seen it before but assumed they work the same as ribbon cables.

After a backup, after hours and with the PC still running I opened the PC and with the client watching I unplugged the power to the primary hard drive. He tried to access his data from his workstation with no luck. when I plugged the primary drive back in the server rebooted automatically. With the PC back up and running I unplugged the power to the secondary drive and the client could access his data. When I plugged the drive power back in, the PC rebooted.  As a final test, with the power off, I switched the cables on the drives making the primary the secondary and visa versa. The PC booted fine and when I unpluged the secondary (which use to be the primary) the client could access his data and the PC would also boot from the drive.

SOOOO! The data is on both hard drves and both are bootable. It appears, in my case, that no matter what drive goes, the other drive will need to be switched to the Primary cable for the PC to continue on working.

I think depending on your BIO's and it's options you might be able to set the machine to boot from a secondary drive if the Primary fails but I couldn't find it on the motherboard in this PC.

Craig

[JmcSkiXC]

Hi,

Has anyone had any experience with the "Adaptec Serial ATA RAID 1210SA" card? It claims support for RedHat Linux 7.3 but I am not sure if you just plug it in and it works or whether drivers modification to SME are required.

Well, slightly off-topic, but I have experience with the 1210SA under WinXP- this card is fantastic.  Serial ATA is the way to go for hot-swap capability and speed.  I did a 3-drive (WesternDig SATA 120's) RAID-5 on that card and it works beautifully.  However, WinXp Pro is a far cry from linux.  I can simply vouch for the hardware quality and performance, both are great IMHO.

pwgsc: Those little cables are serial ATA cables, and are hot-swappable if the controller supports it.  The reboots you experienced are more likely due to the power supply fluctuation from connecting/disconencting power through a non-hot-plug power connector.  The better SATA drives have a special connector for that also, different from the standard 4-pin we all know and love.  And there are also adaptors to convert the 4-pin to SATA power.  

[vortex]

Thanks for the reply Craig & JmcSkiXC.

I have had a chance to play with my software raid setup and all seem to be working fine. I have decided to run without a cd connected to IDE 2 slave as my drives are UDMA 2 & the CD is PIO Mode 4. Not sure if that will cause a problem so I will play it safe untill I hear otherwise.

The Adaptec 1210SA sounds good but I have already bought the twin 80GB ATA drives so any hardware raid will have to be good old ATA for now - but I will play around with raid abit more when I get some spare hardware.

Thanks again

[JmcSkiXC]

If you are considering any possibility of future drive upgrades in your RAID array, you may want to think about still purchasing the Adaptec card, and using parallel-to-SATA adaptors.  Highpoint makes them, as do some others.  They allow you to use a parallel-ATA (standard IDE) drive on a SATA controller.  This way you will have more flexibility.  I run one of those adaptors on my home system, and it works a treat.

BTW- I am assuming with 2 drives you are going to run either a striped set (RAID 0), or a mirrored set (RAID 1)?

The CD will not cause a "problem", but it will slow down the performance of that channel.

Good luck!