what Perc card do I use to add a 220S to a PowerVault 725N

Question

I have a PowerVault 725N which has 4x36 GB drives, and I need more space.  I am looking to expand the current storage by attaching a 220S unit to the 725N.  The 220S has two U320 boards.  It is my understanding that I need to add a Perc4 RAID card so that I can attach the 220S to the 725N.   I don't know what card slots are available (or should be available) in the 725N, but I have never added any PCI cards, so it should have at least one slot open.  What slot(s) should be available?  Which Perc4 cards will work (PCI-x, etc.?!?).  Which card(s) are recommended?  Performance is not that big a deal, as I mostly use this NAS for archival purposes.  More interested in compatibility, reliability, and price.   Oh, and what cable do I need to attach the 220S to the 725N?   Thanks very much in advance for answering these basic questions.   john

johnradams · Answer

Well, thanks for the reply, but I'm a little distressed by your answer!   When I bought the 725N, it was my understanding that the unit would/could support lots of storage -- merely 'add more drives.'   A four drive limit is a big disappointment.   I considered swapping the drives one-by-one, rebuilding in between, but that would require either multiple trips to the colo, or one *long* trip.  Also, I then have 4x80 drives laying around gathering dust.  Perhaps most importantly, this 725N is a production box; my thinking was that I could simply insert a SCSI card, 'attach' another bank of drives, and be good-to-go.    For better or worse, I already have a 220S with six 15K SCSI drives: 4x73 and 2x36.   What have other people done when they needed to expand their 725N?  Seems like adding a 220S is a reasonable path to follow?   Has anyone else added (or tried to add) a Perc card to a 725N and attach a 220S?   Thanks for any insight.

Storagetalk · Answer

You'd need a PERC 4/DC or 3/DC but the 725 isn't supported to have external storage attached.  Meaning it may work, it may not.  Dell never tested it.  You'd need a SCSI wide-to-narrow cable.   You're better off just going to the store and buying 4 brand new IDE drives for the 725.  Just get 250GB drives and make a nice sized raid-5 data container.

Storagetalk · Answer

Whoever told you that was flat out wrong.   Well, one approach you could take to it is to delete your data container prior to rebuilding drives one-by-one.  You will only have to wait through the OS partition rebuilds (i don't know if you have HW or SW raid).  Once they're all done, create a data partition and restore the data.   Well there is no expansion path for a 725.  What you have is what you get forever.  I've seen people mostly just upgrade the drives.   But you know what I just realized, I'm questioning if a PERC will even run in this system.  I don't think it'll even fit.  You'd be stuck using a 39160 SCSI card.  Not a RAID card, SCSI card.  Which means all your raiding would be done thought the OS.  And on a 220 HW Raid system, I highly suggest you stay away from that.

johnradams · Answer

Good for you on avoiding this device :-)

Does the Perc 4/DI have an external channel? How do I find this out?

Regarding performance, by "extra work" I assume that you mean that the controller will now have the additional work of handling the drives in the 220S (not to mention that the 2850 system itself will be busy serving up file sother servers, etc.). This might be OK for me, as the 220S will mostly hold archived data (which is accessed infrequently, and tends to be written to only in large transfers after-hours when we migrate a bunch of somewhat old data to the 220S -- formerly the 725N).

On the other hand, maybe I should go ahead and get a 2nd Perc card for the 2850 -- is there room for one? Which card would you use?

Could I also host the 220S from my old PowerEdge 6450 workhorse? Oops, it has a Perc 3/QC with U160 interfaces, so I guess not....

thanks again!!!

Message Edited by johnradams on 11-17-200611:06 AM

johnradams · Answer

Well, thanks for the additional info.  I am thoroughly unimpressed with a NAS that is not expandable.  What a dumb design.  I really apprecaite you saving me from pursuing a path that was destined to fail!   Since the 725N won't support the 220S, my fall-back position is to attach the 220S to my PowerEdge 2850, and then copy all of the data from the 725N to the 220S.  After copying all of the data over, I will no longer need to have the 725N in production use, and can upgrade the drives by removing the 4x80 and replacing with 4x250 or whatever.   For what it's worth, my 725N does have hardware RAID.   Next question: my 2850 has a Perc 4e/DI controller (as reported by the Dell OpenManage Array Manager).  Pardon my rustiness with SCSI, but here goes -- will this Perc card support the 220S, or do I need another card so that I have another 'SCSI channel' or whatever?  Ideally, I simply run a SCSI cable from the 2850 to the 220S and configure the new setup using Dell OpenManage Array Manager.   Feel free to point me to some useful articles.   thanks, john Message Edited by johnradams on 11-17-200610:47 AM

Storagetalk · Answer

This is what I meant by someone told you the wrong thing, when I inquired about one I was told 'it's not expandable'.  (this explains why it ws so inexpensive).  So I just decided not to get it.  All of the early NAS's were not expandable.   If you have an external channel on the 4/DI then yes, it'll support the 220.  But then you're going to have performance issues because your boot controler is going to be doing a lot of extra work.  I wouldn't put my 220 on the same controler that has the boot drives.

dattark · Answer

You can probably split the 220S bus in split bus mode and hook up one side to the 6450 and the side to the 2850. If your requirements are just to store archive data you can get a 39x60 scsi card from dell and run software raid 1 or raid 5 on the side of the 220s hooked up to the 2850.

The built in RAID controller on the 2850 only supports internal drives. If you must have hardware raid, then You will need either a PERC3 or PERC4 card with external connectors and the corresponding SCSI cables for the 22XS enclosure. The 2850 supports the PERC5 with the MD1000 enclosure. PERC5 will not work on your 6450.

If you are able to increase your budget somewhat, pickup a PERC5/E ($900) and a MD1000 from Dell outlet. I've seen MD1000 on the Dell outlet with 15 x 500 GB SATA drives for about $4,000.

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