Raid and again More Raid

[clone]

Hi

I want to go with Raid 5, so I will need a minimum of three harddrives. But I just wondered if all Raid cards support Raid 5 or if I must get a special Raid 5 card???

One more Question: If I already have a HD that store 80 GB can I use that one for RAid 5 use If I get two more 80 GB HDs (Probably not the same brand as the one I already use)???

Thanks!
christianSpears

 

[SCSIRAID]

You didnt say whether the drives are SCSI or IDE.. RAID 5 is usually not supported in the reasonabally priced solutions (which are basically SW RAID). A hardware based RAID card (using an IOP like the i960 with its own memory) will always support RAID 5 but have a larger price tag.

 

[shathal]

If you're going RAID-5, I'd always recommend HW RAID over SW-RAID (speed for one reason among many).

Generally, with RAID, you want to use as homogenous a system as possible. Perferrably, ONE Type/Model/Manufacturer of HD's along with ONE (i.e.: the latest) version of Firmware for those drives.

You can *try* to use "other" drives (since you mentioned 80 GB, I'll assume you use IDE), but this is likely to cause problems. Among others, RPMs, throughput & such may differ - and this *IS* a problem. (Again - try to use identical drives).

There's not many IDE-RAID controllers out there that do RAID-5 AFAIK. Don't even THINK of going Software-RAID - if your OS gets scrwed then your ENTIRE data is gone as well - another benefit of Hardware RAID.

I'd generally recommend going SCSI with RAID for too many reasons to write here in a brief post.

I hope this helps somewhat .

 

[Windogg]

There are some nice IDE RAID5 hardware adapters out there. They typically cost around $250 - $500 depending on what you want. The 3Ware Escalade has usually shown itself as a performance leader. Many people have said that the card does have problems with dissimmilar drives and even similar drives with different firmware.

I personally went with the Adaptec 2400A. It's based on the proven Intel i960 RISC processor used by most SCSI RAID adapters. It's 4 channel so you can have up to 4 drives. It comes with a 32MB ECC DIMM for the write cache and can be upgraded to 128MB but simply dumping a standard 168pin ECC SDRAM DIMM onto the card.

Goto Storage Review for some good info. Also goto Hyper Microsystems for your SCSI and highend needs. They are great (check their reseller rating) and ship for free if you mention Storage Review.

Windogg

 

[QuestionsandAnsweres]

3ware is coming out with a new firmware for the 6000 series of raid cards. they said some people are getting low performance with the cards but this new firmware should fix it

 

[Woodie]

I would strongly recommend SCSI over IDE, for RAID 5 especially. RAID 5 is "striping with parity", which means out of n drives, you get n-1 for data, and 1 for the parity info. So, for 3x80g drives, you get only 160g of useable data space.

With a SCSI solution, you can just keep adding drives, so instead of 3x80g, you could use: 10x18g, giving you 162g as well, but with only 18g of "wasted" space. Also, the SCSI throughput should blow the IDE RAID 5 out of the water, due to the nature of SCSI (doesn't use the CPU for writing to drives, and can send/receive data from all the devices on the chain at the same time).

If you're not as concerned about performance (which you probably arent', since you're looking at RAID 5), you can get older (used) SCSI RAID cards relatively inexpensively ($40-80).

I'm cheap, so use old drives, so chose to use old RAID, so when (not if!) my drives die, I don't lose data or uptime.

--Woodie