Hybrid Internal/External Raid Array

[joshzstuff]

I changed my email address and got locked out of the forum until I could verify, sorry for the delay.

1. RAID6 is more of a factory in large arrays when you need to account for the possibility of loosing more than one drive.
You are right about RAID6 Levish, one reason however I was considering it (RAID 60) is because I don’t really have the backup I should and the extra protection seems like a security blanket (provided performance is not a prohibitive)

Raid 0/1 will likely be the best performance assuming the extra storage space provided by RAID5 isn't needed.

Just to be sure we are on the same RAID page, I am speaking of striped mirrors (RAID10) and not mirrored stripes (Raid 1+0) although the latter would probably assure that the separation would work better. http://www.storagereview.com/guide20...ltLevel01.html
Just making sure we are speaking of the same array, the controllers listed do not claim to support Raid 0/1.

I’ve thought about possibly migrating to one of the space saving RAIDs to delay upgrading the array, however if I can get the performance/stability necessary from the start from RAID 50/60 it would simplify things greatly. (and save $/space)

2. I've got a 3ware 9650se raid array with OLDE seagates (over 4 years old) that manages to sustain 150MB/sec in Raid5. Pretty sure you won't have trouble streaming HD to and from that. It was more of a concern with the old IDE drives that could barely manage 30MB/sec (and got even slower in RAID). Newer 4 drive Raid5 Arrays should do even better so the array controller isn't a issue for a single user.

Agreed Levish, the move to SATA has done wonders for RAID. I’m not concerned at all about the read access to stream HD but I am hoping to be able to EDIT HD in place without moving it to my RAID1 OS array and so the write access comes into question for anything less than RAID10.

[QUOTE=Levish;3474158]The Hotspare is very nice indeed, i find that its a function included in alot of todays controllers

For the drives you listed you really don't need something like the 1680xi, they aren't fast enough to really stress it even with 8 of them.

3. This drive is a desktop drive and rated as such, not for 24x7 useage (keep in mind), if this is a storage array with 24x7 uptime you will want to look for "enterprise drives" which also typically are validated on RAID controllers.

You are correct, I was not planning on this application when I purchased the drives.

UPDATE:
This is how Adaptec and Areca have responded concerning appropriate hard drives:

Adaptec,

With Hitachi, we have no problems, so any "raid edition" drive is good.
I would also not recommend the Western Digital RE2 or RE3 models as they have also some issues at the moment, especially with the high port controllers like the 51245.
The Samsung F1 drives drives are OK, but if you take the HP103UJ models, they must have the firmware lever with "113" at the end (older versions are not so good).

Areca
There are many features we have
implemented in the Barracuda ES.2 (nearline) for the enterprise / nearline
storage solution, such as a more robust mechanical platform and servo,
along with an RV sensor to help mitigate any offtrack writes caused by RVI
that would be seen in these large enterprise solution enclosures. We can
not support the use of desktop drives in these environments as mentioned
above, and for other business reasons. Therefore we can not provide the
change you are requesting below. We have communicated this same message to
the other host bus adapter partners that utilize the Intel Sunrise Lake IOP
in their solutions, that have requested a similar change.

We are however planning on rolling the F/W on the Barracuda ES.2 ( to SN06)
in the mid October time frame that has cont_p disabled as a default. This
new F/W (SN06) will ship directly from the factory, and it will eliminate
the need for customers to flash in the field."

I will compare the entry level “raid edition” hard drives from Hitachi, Western Digital, and Seagate.
Can any one make a recommendation as to their preference among these?

4. If you choose a external enclosure rather than getting a case which can simply accomodate the drives with hotswap bays you are pretty much forced to get controllers with external ports.

Yes and No.
Both controller listed have 1 external 4X 8088 miniSAS connector. So if we are talking only about 4 external drives & 4 internal (+a 5th or 6th for hotspare) then these cards would accommodate me as is. I say “No” because really there is no difference (as far as I have been told) in an externally attached 8088 cable directly to hard drives than one attached to an ‘internal’ 8087 port that is simply routed outside
Or for the ‘neat’ way to do it (but more expensive) see conversion plates:
1-Port SFF-8088 to SFF-8087 Adapter

This could be used for all internal controllers, or for external expansion to the 2 listed above.

How many drives, what array size and what useage are you shooting for

The answer would be that I would like to start with 8 drives {+ hot spare(s)} with the prospect of expanding externally when needed.
I am considering new 750GB’s or perhaps 1TB’s depending on price.

(or the MB/sec you want)?

That is a good question that I am not 100% sure of the answer yet.
If I EDIT AVCHD then the burden would be more on my processor, however if I encode to MPEG2 then the burden falls more on the storage write times.
(I am shopping for HD editing software, Sony and Adobe are in the running, but this is a different thread)
I believe with the old IDE drives, only RAID 0 was fast enough to support HD EDITING, perhaps this is no longer an issue with SATA drives, and of course RAID 50/60 have faster write times than their 5/6 counterparts.

I would take what that PDF shows with a grain of salt. On the last page it puts the areca 1680 at 420 MB/sec read/writes. That seems odd considering my ARC-1280ML can do 830 MB/sec reads and 650 MB/sec writes and it is an older generation card.

Anyway, if you are going to use AS-series seagate drives neither of these controllers will work. I wanted to upgrade to the ARC-1680ix-24 but did not due to the fact that it has compatability issues with the AS series drives and I already has 12 of them from a previous raid setup.

Thank You Sandon, I hoped to get real world perspective on Adaptecs claims (notice to they only compare the Areca w/ 512 cache?)
@ AS-series seagate drives: you are correct, see reply to Levish above

This shouldn't be needed unless you are doing 24+ drives in your array. One important thing (which I missed reading your post) is how many drives are you planning on having? I doubt any of the raid controllers will let you setup which drives are the mirror drives. Do you really need an external enclosure?

I will need the external for both this setup and for future (See reply to Levish above)

Adaptec controllers I believe have a 16 drive (or was it 16TB?) limit when doing parity raid which disqualifies them for me.
I ended up using the ARC-1280ML since it supports the AS drives and I have had no issues with mine.

I have never heard this Sandon, thanks for the tip, I will ask Adaptec support about this. If it is 16TB, would that apply to the volume size? Or the attached drives limit? (perhaps this is because of their fixed 512MB cache?)