H Frequently Asked Questions - HP Smart Array -UX 11i v2 Support Manual

H Frequently asked questions

H.1 How many Smart Array Controllers can I install in my server?
The maximum number of controllers is restricted to the number of PCIe slots not used for other
peripherals. The power rating of the server also limits the number of controllers. For example,
each Smart Array P400 Controller requires 14 W, and each Smart Array P800 Controller
requires 25 W. The server must be capable of supplying adequate power to each controller.
For more information about system power, see the documentation for your server.
H.2 Does the Smart Array P400 Controller support tape and CD drives?
No.
H.3 Can I use third-party (non-HP) devices with Smart Array SAS Controllers?
No.
H.4 Why do the activity LEDs light up on some disks when my server is idle?
The controller performs background activities on the drives when the server is otherwise idle.
For example, Auto-Reliability Monitoring (ARM) scans fault-tolerant volumes for defects and
verifies the consistency of parity data, and Drive Parameter Tracking periodically checks the
performance of drives (normally on an hourly basis).
H.5 What is RAID ADG?
RAID ADG is an extension of RAID 5 that enables additional fault tolerance by using two
different and independent parity schemes. Data is striped across a set of hard disks, just as
with RAID 5, and the two sets of parity data are calculated and written across all the disks
in the array.
RAID ADG provides an extremely high level of fault tolerance and can sustain two simultaneous
disk failures without downtime or data loss. This fault tolerance level is useful for mission-critical
data. For more information, see the RAID Technology Overview, at:
http://docs.hp.com/en/netcom.html#Smart%20Array%20%28RAID%29
H.6 What does the auto-fail missing disks at boot option do?
The auto-fail missing disks at boot option controls the power-on behavior of the
HP-UX RAID controller when configured disks are missing. Auto-fail is enabled when the first
logical drive is created by the saconfig utility. You can disable it with the saconfig -F
command.
As an example, consider the following scenario:
The boot volume is on a RAID logical drive.
The server is powered off.
The cable for an enclosure containing configured disks is accidentally disconnected from
the controller.
Disks belonging to the boot volume are still connected to the controller.
The server is then powered on.
If auto-fail is enabled in this scenario:
During POST, the controller fails the missing disks.
Non-fault-tolerant logical drives are listed as FAILED.
Fault-tolerant logical drives transition to Interim Recovery (degraded) mode or to FAILED
depending on the number of disks the logical drive is missing.
The server then begins booting HP-UX.
During boot, the ciss init script detects the degraded/failed logical drives and generates
an error that instructs you to run sautil. The sautil utility displays the degraded/failed
logical drives and failed disks. At this point, you can power off the server, reconnect the
disks, and boot again; or reconnect the disks and run the sautil accept_media_xchange
command to change the disks and logical drives back to OK state. For more information,
126 Frequently asked questions