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st0ne_c0ld
Asked: 2012-06-28 02:34:55 +0800 CST

RHEL5 do not see sas tape library

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We have a tape library which is connected to a server by SAS link. Server is running OS Linux. OS doesn't see the tape library in /proc/scsi/scsi . We tried to rescan scsi bus(*1), but it didn't help.

What could we do to access it?

PS:The main goal is just to see it connected to the server We also have storage system connected to the same HBA. Servers,storage and library vendor - HP.

*1 - for each host we run echo '- - -' > /sys/class/scsi_host/hostN/scan

linux sas autoloader tapedrive

2 Answers

  1. I'd like to see more detail. Please provide the server model, tape drive information and explain how it is onnected to the server. Which backup software suite will you be using?

    In general, a SAS tape device should be connected to a dedicated SAS HBA. In most HP installations, this is really an LSI-based controller, so you'd be working with the mptfusion set of drivers. So grep -i mpt in your dmesg output and the relevant log files in /var/log...

    If the driver/module is loaded, you don't need to rescan or do anything manual to recognize the drive.

    This may be different if you're connected directly to an HP Smart Array controller... So please clarify.

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  2. Best Answer

    We rebooted the server and tape library appear in /proc/scsi/scsi and /dev/ files created properly. It is not the way it should work. But it helped.

    Probably it is because of SAS "topology map" or something like this. Because after reboot - multipathd stopped showing error messages about disconnected links.(we also tried to reload multipathd before reboot) Looks like HBA or driver remember what is in HBA ports until reboot.

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