Are you running the latest Firmware/BIOS updates on your Mylex card? I
was having trouble similar to what you described until I upgraded the
Firmware on my Mylex card. Please check the Mylex web site in their
downloads section and make sure you have the most recent firmware BIOS
updates installed. There is also a buglist for the Firmware updates in a
PDF file in that general area of the Mylex site.
For the latest updates for your controller (if you are not already using
them), check out the following page:
http://www.mylex.com/products/dac960/drivers/filmbios.html
And for some helpful information about the Mylex cards under linux:
http://www.dandelion.com/Linux/DAC960.html
http://www.dandelion.com/Linux/
BTW, I am running 4 drives per channel. I am not aware of the bus
limitations reguarding LVD drives, although I'm pretty sure there is some
documentation on it on the Mylex site, although you have to dig for it.
I am using a cable designed for five drives and an LVD terminator, and the
bus lines are braided. I don't imagine someone would sell a cable
designed for that many LVD drives if it violated the specification,
although it may be that I am just naive and someone sold a cable for SE
drives in an LVD package. If the firmware doesn't fix the problem,
running your drives in SE mode at 20MHz instead of LVD mode at 40MHz may
stablize things (that's 40MB/s as it is running 16 bits at 20MHz). Make
sure you use an SE terminator and jumper your drives to force SE mode if
that option is available on your drives. And please back up any data you
care to save before trying this.
I might add that the Mylex tech support was very helpful.
If you've already upgraded your Firmware and you already read the above
pages, please disreguard this message. Best of luck to you.
-Theron
--
On Wed, 8 Sep 1999, Leonard N. Zubkoff wrote:
> From: "Kent Nilsen" <[EMAIL PROTECTED]>
> Date: Wed, 8 Sep 1999 13:48:11 +0200
>
> I've also got some questions concerning the Mylex 960:
>
> I've got a JBOD box with 5 Seagate Elite23 disks, which is connected to a
> Mylex DAC960 PG controller (channel 0). On channel 2 (internal) I've got 5
> Barracuda 18Gb disks. The machine is a PIII450 with 384Mb RAM, a
> DAC960PG, Supermicro Dual PII mainboard with onboard 789x SCSI. Running
> Mandrake 6.0, kernel 2.2.7 with the latest patches available
>
> The Elites used to be mounted on a Sun computer, and caused no trouble
> there. The barracudas were mounted in a JBOD cabinet on a Sun, and caused
> no trouble. However, when I put the Barracudas in the server, I had to disable
> Tagged command queuing to make it work (else it said "bad tag received from"
> whatever disk was ID 0.). I also connected the JBOD cabinet with the Elites to
> channel 0 on the DAC960. I got that initialized, and formatted it, mounted it,
> and finally started using it. After a while I began to get some weird messages:
>
> DAC960#0:Physical Drive 0:10 Error Log: Sense Key=6, ASC=29, ASCQ=00
> ------------"---------------------------------------------: Information = 00000000
>00000000
>
> And that message is repeated for each disk (0:11, 0:12 etc). I don't have any
> disks on the lower addresses (because the disks were set this way when I took
> over). /proc/rd/status says "OK", /proc/rd/c0/current_status reports no
> problems.
>
> The above messages indicate that a bus reset has occurred. Starting with the
> 2.2.4 version of the DAC960 driver a counter of bus resets is kept for each
> drive rather than logging errors every time. If a command to a disk drive
> is not completed within 6 seconds, the DAC960 times it out, resets, and
> reissues the command. This is not a problem unless it occurs frequently.
>
> The "bad tag returned from drive" tends to be a catchall error that generally
> indicates buggy firmware in the disk drive. Needing to disable tagged command
> queuing also indicates a likely problem. Have you checked with Mylex to be
> sure you have the latest version of DAC960PG firmware and whether there are
> known problems with the firmware in the Seagates?
>
> It takes me 3-4 minutes to mount it, and these error messages pops up all the
> time.
>
> The last part is the System drive setup... I tried to add 5 more Elite23
> disks on Channel 1, but when I plugged the disks in without setting them up,
> the DAC960 1: Did not set up any of the previously configured system drives.
> 2: Did not find the last 23Gb disk (only 4 of 5 disks, and this box just came
> from another server that's been running on the disks for almost a year.). 3:
> When I tried to delete one system drive (the other 23Gb Elites) to make a new
> bigger one, it says it can only delete the last created system drive. That's
> my 80Gb RAID5 disk with lots of important data! This isn't a big problem,
> I've got backup, but taping in and out takes time. And does that limit really
> increase security or whatever it's there for?
>
> The above seems strange. The DAC960 should have still been happy with the
> configuration of the existing drives, leaving the new ones as unconfigured, and
> allowing you to build a new drive group and logical drive out of them.
>
> All in all, is the DAC960 a very "strict" card that won't work with cables
> that work with most others? My cable length is about 1.50 meters, with a 0.6
> meter cable and 0.9 meter approx inside the JBOD. My terminators are active,
> and I have no 68->50 pin converters on the chain.
>
> First, 5 drives per channel may well be violating the UltraSCSI specification.
> The DAC960PG might well be quite picky in this regard. Have you tried setting
> the transfer speed down from 40MB/sec to 20MB/sec to see if avoiding the faster
> signalling helps?
>
> The newer Ultra2/LVD controllers seem to be a lot better in regard to cabling
> issues.
>
> Leonard
>
