How to make DS2100 work with D-class or R-class?

[Raghunandhan Srinivasan]

Hi
I have a HP 9000/820/D280 system which has a SE SCSI card. We bought a DS 2100 (part number A5675A) recently and sent this to Atlanta where the system was located. The HP UX sysadmin reported that the "array was not picked up by the system at all". I would like to know
1) if this D-class server will ever work with a DS2100.?
2) If not, do I need to change my server or buy a specific card to make it work?.
3) Has anyone got a DS2100 to work with the model that we have.?
Will appreciate any pointers. Thx for your time.
Raghu

[Patrick Wallek]

You need to look at the DS2100 and see what type of SCSI interface it has and then get the appropriate SCSI Card for the D280.

[Mel Burslan]

ds2100 is an ultra3 scsi device but both R class and D class are considered to be archaic machines, even though they both have PCI hardware extension chasis, I do not believe any PCI Ultra3 SCSI card will have drivers for those. You may luck out with R class as it is much newer than D280 but I would not get my hopes high on neither.

[A. Clay Stephenson]

Here is a quote from the Dec. '01 Configuration Guide:

"The HP Surestore Disk System 2100 is not operating system specific. It is designed to work with any Ultra3 SCSI LVD equipped workstation or server and is backward compatible to slower SCSI LVD interfaces. Please be aware that when the DS2100 is configured for single-ended (SCSI/SE) operation, only one unit with up to four drives may be connected to the SCSI interface."


It would appear that operation with your SE-SCSI bus is possible although you would be much better off with an HVD SCSI controller in your D or R box in turn connected to an HVD/LVD SCSI bus translator. You would be better off still by choosing something other than a D or R-box since your only choices with these do not include LVD SCSI.

Plan C. Forget about the DS2100 and find yourself a Jamaica enclosure (A3312). These JBOD's will accept eith SE or HVD SCSI Disk modules and are available on the used-equipment market.

[Leif Halvarsson_2]

Hi,

If I remember correct the D and R class servers has a Narrow SE connector. It should be possible to connect a LVD device to that bus (if you can find a 50-68 pin adapter cable) but you are limited to the performance of the NSE bus. It is NOT possible to connect a LVD devise to the HVD bus (unless you use a LVD-HVD bridge).

[Leif Halvarsson_2]

Hi,
Seems as HP has a such device (but rather expensive). I dont know if it is still avialable:
http://h30094.www3.hp.com/product.asp?sku=1892520&jumpid=ex_2910_quigosmb/ink/2756

Another source:

http://www.disuk.com/site/html/converters/rt-lvd-hvd.html

[Raghunandhan Srinivasan]

Thx for all your responses.
As I am running short of time, I plan to buy the convertor.
has anyone got this to work with this converter. Any gotchas?
Raghu

[A. Clay Stephenson]

The HVD/LVD SCSI bus convertor will only help you if you have at least one HVD controller in your D-box. If all you have is an SE-SCSI controller there is not point in buying one.

[Ted Buis]

If I remember correctly, the only HSC based SCSI card was HVD (FWD) SCSI which will not work with SE or specifically the DS2100 at all. The was a SE SCSI card but it was EISA, and I think support for EISA was dropped, so I don't think you have any drivers for the SE card in the D280. It would certainly be an unsupported configuration with any converter.

[Raghunandhan Srinivasan]

Thx, I have decided to return the DS 2100. What JBOD can work with this server.
Raghu

[Ted Buis]

Like the D280, everything is out of production that was designed to work with it.
You should verify that you have the FWD SCSI interface in the unit (A4107A ??). The units that were designed to work with it were the A3311A (deskside) or A3312A (rack mounted) HA enclosure with FWD SCSI disks. The HVD10 should also work.

[A. Clay Stephenson]

The JBOD you need is an A3312 which will hold up to 8 half-height drives. The enclosure is actually split into two separate buses so that you could treat this as two arrays with 4 drives each or daisy-chain them for one bus. Both FWD/HVD and SE SCSI disk modules are available on the used market. It's even legal to use one side of the JBOD as FWD/HVD SCSI and the other side as SE/SCSI.

[Chris Wong]

I just set this up on a D380. I am using the built-in single-ended SCSI connection with a 5181-7077 cable to the DS. It works. Running 10.20 with hardware extensions 3.0

[Raghunandhan Srinivasan]

Thx for all your responses. This is the best forum I have ever seen. The sys-admin complained he had no rack space for the Jamaica. We decided to make use of the existing array (which we were suprised to hear that it existed) and add additional disks. We were told it is a A3700AB array and we need to buy another 4 x 4 = 16 Gigs. Hopefully we find this beasts (A3702A) in the used market. Here is the link which supposedly have them.
http://www.pmount.com/prod_show.asp?ss=STOR
Raghu

[A. Clay Stephenson]

The A3700 is the Model 12H AutoRAID and will hold up to 12 Disk Modules ranging from 4GB to 36GB. It is an HVD/FWD SCSI only device and you really need 2 A4107A FWD/HVD controllers to get good performance. If you want good performance out of one of these old beast the key is to buy twice as much disk as you really need (and leave the space unallocated) so that the 12H stays in RAID 1/0 at all times. This can make a 5X difference in performance.

[A. Clay Stephenson]

By the way, if you use only 4 4GB disks in an AutoRAID, expect only about 8GB of usable space. One drive will be used for an "Active Spare" unless disabled and the other will be used for redundancy. You really need 6 4GB drives to approach your desired 16GB of usable storage. You should note that the Model 12H is NOT a JBOD but a true disk array.

[Raghunandhan Srinivasan]

Thx for the heads up. Is there any reason why we cannot get use higher capacity drives in this array. We should not be mixing existing 4 Gig with 36 Gig (for example). ?
Raghu

[A. Clay Stephenson]

Because of the way the AutoRAID accounts for Active Spare space (there must be enough capacity to cover the failure of the largest single drive) and because the RAID mode can automatically shit from RAID1/0 to RAID5, it becomes very difficult to calculate array capacities when you use combinations of drives. For example, 4 4GB + 1 36GB drive would yield exactly the same capacity as 5 4GB drives -- if the array defaults are used. You need to buy at least 2 of the largest disks to reap any benefits. A good compromise would be the 9GB drives. They are still common and are a reasonable compromise. 4 x 9GB would give you about the capacity you are looking for; 6 X 9GB would yield good performance coupled with good reserve capacity. By the way, eventhough the 12H uses 2 HVD external SCSI buses, it uses four internal SE-SCSI buses so that the disk modules themselves are actually SE-SCSI.

[Ted Buis]

Firmware updates might be needed to the array. Likely you need at least two of a drive size for it to make use of the extra capacity and maybe more. Check
http://h20000.www2.hp.com/bizsupport/TechSupport/Home.jsp?locale=en_US&prodSeriesId=33733&prodTypeId=12169

[Ted Buis]

or better http://h20000.www2.hp.com/bizsupport/TechSupport/DocumentIndex.jsp?contentType=SupportManual&locale=en_US&docIndexId=179911&taskId=101&prodTypeId=12169&prodSeriesId=33733

[Chris Wong]

"Individual disk modules with different RPM and capacity can be mixed & matched within the array". Keep in mind: "When Active Hot Spare is enabled, space is reserved for rebuilding the LARGEST disk drive, reserved space is spread across all the disks". If you add a 36GB disk, the reserved space size will increase from 4GB to 36GB. Also "Atleast 2 higher capacity disks must be added to utilize their entire capacity. "It is also important to note that adding only one or two higher capacity disks to an array of smaller disks may not yield the expected capacity. When only 2 higher capactiy disks are added to the array, the upper segment created by the new larger disks will be used for the larger Active Hot Spare and parity requirements, giving little gain to available capacity. Once 3 or more higher capacity disks are added, the increase in storage capacity is significantly higher".

[Raghunandhan Srinivasan]

Thx Clay for the explanation. Thx Ted for the firmware tip. I also read Chris note on the effect of mixing drives of different capacities. As this is a developement server, I am not going to worry about redundancy etc. I am just going to buy
4 x 9GB disk then and stripe it and mount it as a separate volume of 36 Gigs. Thx
Raghu

[A. Clay Stephenson]

Not if you are using an A3700 (Model 12H AutoRAID) you're not. You haven't grasped the significance of AutoRAID: You have absolutely no control over the layout of the disks or LUN's. You can disable Active Spare and Auto Rebuild but the array is going to reserve space for redundancy. If you plan on gettting anything near 16GB out of 4X4GB drives then prepare to be disappointed.

[Raghunandhan Srinivasan]

Oh, my god. So 4 x 9 would still give me the additional disk space (16 something instead of 36 Gigs) or I replace the entire array with 9 Gigs. Install O/S, create the same and restore from tape? Right.
Raghu

[A. Clay Stephenson]

4 X 9GB with Active Hot Spare On would give you about 17GB capacity and with Active Hot Spare Off would give you about 24GB.

For 6 X 9GB, the values are approximately 32GB and 39GB respectively.

I strongly reccomend the 6 X 9GB configuration because your target storage range of 16GB would now be allocated fully as RAID 1/0 rather than a mixture of RAID 1/0 and RAID 5.