Hardware : RAID : RAID drives
  
RAID drives
 
Page Contents
Understanding RAID drive failures
Installing the drives in your Observer Platform appliance
How to reseat a failed RAID drive
How to troubleshoot a RAID drive that has failed before
How to replace a RAID drive without a tray
How to replace a RAID drive with one already in a drive tray
How to handle hard drives properly
How to monitor the RAID drives through email notifications
The RAID drive failure is rare but does occur. You should have spare drives on hand and a plan to identify and replace failed drives.
RAID drives are a field-replaceable part.
Understanding RAID drive failures
Each RAID drive can encounter soft and hard errors during its lifespan. You should have spare RAID drives set aside to deal with these RAID drive failures.
RAID 5 tolerates one drive failing completely, and the RAID can still operate in a degraded state. When the failed drive is replaced, the RAID array starts to rebuild. How long the rebuild takes depends on the array size and whether it needs to write new data at the same time. If a second drive fails during the rebuild, the array is broken and must be recreated.
There are two types of drive failure:
Soft error: an error sent by the drive to the RAID controller—an error causes the drive to be removed from the RAID array.
Hard error: a physical drive failure—an electrical or mechanical error renders the drive completely inoperable.
Note: We recommend configuring the e-mail notification option in the RAID controller setup.
For soft errors, reinserting the drive into the appliance usually brings it back into the array. The error generally has to do with the drive having mapped some bad sectors, which is fairly common. In many cases, the drive can run normally after being reinserted into the appliance. However, if this event happens, we recommend replacing the drive with a spare and shipping the problem drive back for testing and replacement per your hardware maintenance arrangements. If you choose to reinsert the drive, please notify Technical Support so that if it happens again with the same drive, it can be replaced.
If a hard error is detected, the drive does not operate and requires replacement. It is critical to have at least one spare new drive on hand, and probably more than one. In general, we recommend that for every eight hard drives in your GigaStor probe that you have one replacement drive.
Example number of total drives in RAID
Number of recommended spare drives
8 drives
1
24 drives
3
48 drives
6
96 drives
12
Your packet captures are available while the RAID is running in a degraded mode. However, all captured data on a GigaStor appliance is lost when two or more drives experience a hard error at the same time (or if the second drive fails during the time the first drive is rebuilding). From the time when the first bad drive is swapped until it has completed the rebuild period, your captured data is at risk.
For optimal data redundancy, we recommend that two identical appliances capture the same set of traffic. If this is not practical, the next best option might be having a smaller GigaStor appliance capturing the same set of traffic. Then, if the first GigaStor has a drive failure followed quickly by another, your packet captures would still be instantly available from the other system. Use filters to limit the captures to only the most critical traffic to extend the troubleshooting time available. The point is simply to have a backup plan to address even this unlikely drive-failure scenario.
There is a RAID option to set aside one of the drives in the array to be allocated as a hot spare, leaving the rest available for capture. If a drive fails in this scenario, the RAID controller automatically notifies you and includes the hot spare drive into the array. You lose storage overall, because that spare drive is not available, but the drive swap is handled automatically. Please see the Areca 1883 Series documentation (PDF) for details.
Installing the drives in your Observer Platform appliance
Failure to install the drives in the proper location will result in poor read and write performance until the RAID array volume is rebuilt.
Follow these instructions to install the drives correctly before starting the appliance.
Stickers on each drive identify which slot it should be installed in. The drive labeled 1 must be installed in the upper left slot of the appliance.
1. Make sure that the appliance is turned off.
2. Locate the drives that comprise the array. The drives are labeled to show you where they should be installed in the drive cage. (Image may not exactly match your product.)
Figure 12: Appliance front (product may vary)
3. Gently insert each RAID drive by squeezing the tabs and sliding the drive into place until the tabs can engage the slots on both sides of the drive. Do not use force!
Slightly lift the drive tabs to ease insertion.
Figure 13: RAID drive
4. Repeat until all of the drives are installed as labeled.
You should push each drive slightly to ensure that it is fully seated. Additionally, you may want to visually inspect all of the drives from the side to verify that they are all sitting at the same approximate depth. Check any that are protruding while the system is turned off.
5. Turn on the system, and check that every RAID activity LED light is lit. If not, turn off the system, reinsert the corresponding drive into its cage, and confirm that it clicks into place.
 
The RAID drives are now in place and you can turn on the appliance.
 
How to reseat a failed RAID drive
Reseating a drive shown as FAILED in the RAID card Event Viewer is the first troubleshooting step.
1. Check the RAID card Event Viewer to see which drive is labeled as FAILED.
2. Pinch the sides of the RAID drive tray handles.
3. While continuing to pinch the handles, remove the RAID drive from its cage.
4. Reinsert the RAID drive until it clicks into place.
The drive handles should be securely seated into the notches of the cage.
 
 
How to troubleshoot a RAID drive that has failed before
If the same drive repeatedly fails, then it may indicate a problem with either the drive or the appliance. You can determine which of these is at fault by troubleshooting with a known good or new hard drive.
 
Physical access to the appliance is needed when troubleshooting a RAID drive that repeatedly fails. This is due to needing to reseat the drive, replace the drive, or both.
You must be prepared for server downtime and lost data. If any other drive fails during reseating of the drive or its replacement, the RAID array fails and your data is lost.
You must be prepared for slower RAID performance during this procedure. When a single RAID drive is removed from the RAID, the RAID continues to work but in a degraded state. Your RAID performance returns to normal after a good hard drive returns to the RAID array.
The RAID card is informing you that a hard drive has encountered an error. The same drive has encountered errors before.
If these steps do not resolve the failed RAID drive, then more advanced troubleshooting is necessary. The appliance may need to be returned for service. In this case, contact Technical Support.
 
 
1. Confirm which drive is having issues by doing one of the following or both:
a. Check the RAID activity lights on the front of your appliance to spot a failed drive.
b. View the RAID card Event Viewer to see which drive is labeled as FAILED.
2. Remove the failed drive.
If all other drives are inserted and working properly, it is safe to remove exactly one hard drive while the appliance is turned on.
a. Pinch the side of the RAID drive tray.
b. Remove the RAID drive from the cage.
3. Reinsert the same hard drive to the same slot by sliding the drive in until it clicks firmly in place.
Figure 14: Repeated drive failure
You successfully reseated the hard drive. If this fixes the issues, you are done. If the drive still fails, then wait a few minutes and continue to the next steps.
4. Remove the failed drive if reseating it did not fix the issue.
If all other drives are inserted and working properly, it is safe to remove exactly one hard drive while the appliance is turned on.
a. Pinch the side of the RAID drive tray.
b. Remove the RAID drive from the cage.
5. Replace the hard drive with a known good or new drive of equal storage capacity.
a. Separate the drive tray from the drive by removing the four screws on the bottom.
b. Attach the drive tray to a new hard drive by inserting and tightening the four screws to the bottom of the hard drive.
c. Insert the new RAID drive and ensure that the drive handle sides are securely seated into the notches of the RAID cage.
Figure 15: RAID drive
 
How to replace a RAID drive without a tray
1. Remove the failed drive.
If all other drives are inserted and working properly, it is safe to remove exactly one hard drive while the appliance is turned on.
a. Pinch the side of the RAID drive tray.
b. Remove the RAID drive from the cage.
2. Separate the drive tray from the drive by removing the four screws on the bottom.
3. Replace the hard drive with a known good or new drive of equal storage capacity.
4. Attach the drive tray to a new hard drive by inserting and tightening the four screws to the bottom of the hard drive.
5. Insert the new RAID drive and ensure that the drive handle sides are securely seated into the notches of the RAID cage.
 
 
How to replace a RAID drive with one already in a drive tray
1. Remove the failed drive.
If all other drives are inserted and working properly, it is safe to remove exactly one hard drive while the appliance is turned on.
a. Pinch the side of the RAID drive tray.
b. Remove the RAID drive from the cage.
2. Insert the new RAID drive and ensure that the drive handle sides are securely seated into the notches of the RAID cage.
 
 
How to handle hard drives properly
Be especially careful when handling and installing the hard drives. Proper handling is paramount to the longevity of the drive. The internal mechanism of the hard drive can be seriously damaged if the hard drive is subjected to forces outside its environmental specifications.
 
Caution: When transporting the hard drive, always use an anti-static bag and the shock-absorbing packaging in which the hard drive was delivered to you.
Always handle only one drive at a time.
Always have one hand under the tray to support the weight of the drive when removing or inserting it.
Always hold the hard drive by grasping the long sides that have mounting holes.
Always use an anti-static mat and wrist strap when handling the hard drive.
Never stack hard drives on top of each other.
Never hit the hard drives in any way.
Never touch the components on the circuit board assembly.
Never cover the small hole on top of the hard drive.
Never place the hard drive near equipment that produces strong magnetic fields.
Avoid moving any hard drive that is turned on and operating.
Avoid exposing the hard drive to extreme changes in temperature to minimize the risk of condensation.
If the temperature difference between the storage location and installation location exceeds 50°F/10°C, for temperature acclimation purposes, leave the hard drive in the new location overnight (or at least two hours) before turning it on.
 
How to monitor the RAID drives through email notifications
You can receive email notifications of RAID events. To do this, you must configure the RAID controller with an SMTP address for sending email, up to four email addresses as recipients, and the type of notifications to be sent.
Caution: VIAVI recommends you contact Technical Support before making any changes to the RAID. You could lose data stored on the array or reduce its performance if a mistake is made.
VIAVI uses a third party monitoring tool to monitor the RAID array developed by Areca. With it, you can be notified by email if there is an issue with the RAID array.
2. In the leftmost panel, expand the System Functions list and click Mail Configuration.
Figure 16: RAID array email notifications
3. Complete the page with the details for your SMTP server, email addresses to send to, and the type of notifications to send.
4. Select Confirm The Operation, and click Submit.
5. Close the web browser and minimize the Areca application to the taskbar.
 
Now that email notifications are set up, your configured recipients are sent an email message any time a new RAID issue occurs.