RAID
RAID Controllers
| Hostname | RAID Controller | OS | User Manual | Web Interface Address |
|---|---|---|---|---|
| Taro.unh.edu | Areca Technology Corp. ARC-1231 12-Port PCI-Express | RHEL 5 | Areca ARC-1xxx | http://10.0.0.97/ |
| Pumpkin.unh.edu | Areca Technology Corp. ARC-1231 12-Port PCI-Express | RHEL 5 | Areca ARC-1xxx | http://10.0.0.99/ |
| Gourd.unh.edu | Areca Technology Corp. ARC-1680 8-port PCIe SAS RAID Adpater | RHEL 5 | Areca ARC-168x | http://10.0.0.152 |
| Tomato.unh.edu | 3ware Inc 9000-series | RHEL 3.4 | - | - |
| Old Gourd | Promise Technology, Inc. PDC20378 (FastTrak 378/SATA 378) | RHEL 3.4 | - | - |
| ? | 3ware Inc 7xxx/8xxx-series PATA/SATA-RAID | - | - | - |
| Pepper.unh.edu | Silicon Image, Inc. SiI 3114 | RHEL 3.4 | - | - |
| Old Einstein | Marvell Technology Group Ltd. MV88SX6081 8-port SATA II PCI-X | RHEL 5.3 | - | - |
New RAID cards: ARECA
The Areca cards in Pumpkin, Taro and Gourd (the new Einstein hardware) can all be accessed with a web browser. The interfaces are all on the backend network:
You log in as "admin" with the standard root password missing the prefix part.
Working with Areca RAID devices
These are my notes from testing out the Areca card in Gourd, and should serve as brief howtos for various features of the RAID cards.
Pass-through drives
Pass-through drives are not controlled by the RAID card. They function as an independent scsi device plugged directly into the system, and are not part of a RAID set. [Gourd] currently has two pass-thru disks set up in a software RAID. These are the steps I took to add a new pass-through device on [Gourd]:
1. Insert the drive into the drive bay
2. The drive should now be visible in the Areca web interface. Expand the "Physical Drives" folder in the left column and then select "Create a Pass-Through disk".
3. Select the disk you want to create as a pass-through disk and then check the confirmation box before clicking the Submit button.
RAID Sets and Volumes
Setting up a hardware RAID on an Areca card is a two step process. First you have to add the drives you want to use to a RAID set. You need to make sure you add the correct number of drives for the RAID level you want to use, but beyond that all you're doing at this point is making a group of drives you can create a volume on. You'll choose the RAID level when you create the volume. To create a RAID Set:
- Click "Create a RAID Set" under RAID Set Functions
- Select the drives you want to add to the RAID Set. You can only add Free drives to a new RAID set.
- Confirm the operation and click Submit
You now have a RAID set, but in order to use it as a drive you need to create a Volume set. This is where you will select the level of RAID to use. The Areca card will only give you the options for the RAID levels that are possible on a given RAID set, so for example if you only have two drives you can't create a RAID 5 or 6, which requires at least 3 or 4 drives, respectively. The Areca cards support volumes of different RAID levels on the same set of drives. The important settings to bear in mind are the Volume name, which you should set to something more useful than "Volume Set #00004", the RAID level, and the SCSI Channel/ID/LUN. Unless you have a reason to change them you can accept the defaults on everything else. To create a Volume Set:
- Click "Create a Volume Set"
- Select the RAID set you want to create your Volume on and click Submit
- Choose the settings you want to apply to the Volume Set, confirm the operation and click Submit
If you select background initialization you will be able to access the Volume immediately, but if you choose foreground initialization you have to wait for initialization to finish before using the volume. Depending on the size of the volume it may take a long time to initialize (two hours for a 500gb RAID volume, in my experience), so you might want to go and make yourself a cup of coffee.
Adding/removing scsi devices on the fly
When you create a RAID volume on the Areca card the system won't see it until you reboot. There is a way to add and remove scsi devices without rebooting by using the proc interface.
You should have the values for Channel, SCSI ID and LUN from when you added the drive, but if not they're listed next to the volume name on the Areca web management interface. Note that the following command takes four values, but you only get three from the Areca card. The values from the Areca card should be the last three, and the first value should be zero. Use this command as root (sudo won't work) to add a scsi device:
root@gourd# echo "scsi add-single-device 0 0 0 1" > /proc/scsi/scsi
Once you've run this command your volume should appear in /dev/sd* with the other scsi devices. To remove this device you would use a similar command:
root@gourd# echo "scsi remove-single-device 0 0 0 1" > /proc/scsi/scsi
Possible rescue techniques
DO NOT ATTEMPT THIS WITHOUT TOP SUPERVISOR PRESENT
some unchecked advice in a forum
Software RAID
RAID volumes in Linux are created using partitions, so the first step in creating a software RAID is creating the partitions you want to add to the RAID. Once you have the partitions created use the following command to create a RAID 1 mirror of the two partitions:
Old RAID cards
The documentation for the controller should be available in /usr/local/doc/3dm2. There should be a deamon running, start it with "/etc/init.d/3dm2 start" With the deamon running, the device can be checked and manipulated using a web browser on the local machine pointing to http://localhost:888/. Log in as administrator with the root password.
More recently (2006) we no longer run this deamon, instead the RAIDS can be querried and controlled with tw_cli, in /usr/local/bin. Type tw_cli help for help. You must be root to run this program.
Examples (must be root):
tw_cli help info tw_cli info c0 # info for card 0 tw_cli info c0 u0 # info for unit 0, Tells you it is RAID-5, Status OK, size, Stripe size tw_cli info c0 p0 # info on disk0 on card0, size, serial number. tw_cli info c0 p0 model # model number of disk (Maxtor 6B200S0)
Be totally wicked careful with any of the other commands PLEASE
TOMATO:
Contains a RAID with 12 Maxtor Diamond Max 10 drives (300GB, model number: 6B300S0). Data Sheet
Size: 300 GB Spin: 7200 RPM Buffer: 16 MB Seek: <9 ms Latency: 4.17 ms] Current/Power - not specified. 1.2 Amp/ 15 Watt is a good guess
OLD GOURD:
Contains a RAID with 8 Maxtor drives (251GB, Model number 7Y250M0)
