RAID 1 - 4 Drives

R

ReD-DaWg-OnE

n00b
Joined
Jul 23, 2009
Messages
36
I had a new client contact me with very specific requests for a server quote. I tried to meet with them to better assess their needs but they weren’t available.

He wants a RAID 1 with 4 drives, I would try to talk him into a RAID 1 with hot spare and a good DR solution but he is very specific.

I have looked on Adaptec’s and LSI’s website for SAS controllers which support this but I wasn’t able to find any documentation about it.

Do you guys have any ideas?
 
It all depends on how much capacity if wants to be left with.
If only the capacity of a single drive, then either a 4-way mirror or a duplex-ed mirror (mirror of a mirror) will give him that 25% capacity and higher protection level.

If 50%, then two mirror set will do (although a poor choice vs just going with RAID 6).
With two mirror sets, you still stand a chance of losing both drives from the same mirror set and not being able to recover.

If no DR in place, then I agree with you partially. I agree with the allocation of one drive or more for DR but a hot spare is less useful than just going with a 3-way mirror (here the "hot spare", so to speak, is fully active and boosting read performance).
 
All he wants is a 4-way mirror, I assume he lost data due to a hard drive failure and isn't thinking about other possible failures that can impact his business.

I couldn't find any documentation on any controllers which specifically said they support this.
 
4 way mirror won't mean a thing if the card dies. The OP sounds like he knows what's going on so my post is redundant, So... Raid 1 of 2 drives w/ HS or RAID 10, both with a better backup solution is what he needs. Definitely though, follow up and verify why the odd request. Sounds like another Small Biz owner confusing the purposes of RAID and Backup
 
Greetings

ZFS would also be able to do this, no special hardware controller required, just 4 drives attached to 4 sata ports is all that's needed.

Cheers
 
ReD-DaWg-OnE said:
All he wants is a 4-way mirror, I assume he lost data due to a hard drive failure and isn't thinking about other possible failures that can impact his business.

I couldn't find any documentation on any controllers which specifically said they support this.
Click to expand...

I really don't see the issue here.

Let him have it. Just make him purchases more drives for DR.
Remind him how if the volume gets corrupted or files are inadvertently deleted, it is all disks that are affected.

A 4-way mirror + a good backup strategy has no negative. :)
 
I proposed a traditional 2 drive RAID 1 with a hot spare, but he insisted that he has a lot of backup experience. I plan on demoing his a Datto Sirus device and see what he thinks.

I forgot to mention the RAID needs to be on a Windows 2012 server.
 
Once again, there is little purpose to a hot spare in RAID 1 unless your controller limits you to 2-way mirrors.
 
ReD-DaWg-OnE said:
I proposed a traditional 2 drive RAID 1 with a hot spare, but he insisted that he has a lot of backup experience. I plan on demoing his a Datto Sirus device and see what he thinks.

I forgot to mention the RAID needs to be on a Windows 2012 server.
Click to expand...

*snerk* wow.. sounds like he doesn't know what he's talking about.
To me that reeks of RAID == backup thinking... Which doesn't help at all if say.. the whole machine gets slagged by a lightning strike or something.
 
FnordMan said:
*snerk* wow.. sounds like he doesn't know what he's talking about.
To me that reeks of RAID == backup thinking... Which doesn't help at all if say.. the whole machine gets slagged by a lightning strike or something.
Click to expand...

I am very familiar with with backup/DR solutions, I am a Datto Partner and have deployed there devices to several clients. I also have experience with Zenith BDR and am a Zenith partners as well.

Thanks spectrumbx, until this client insisted on this particular setup I wasn't even aware of anything other than a 2 way RAID1. I didn't understand the hot spare being useless if it supported a 3 way mirror at first as I haven't ever used more than a 2 drive RAID 1.

Thanks for all the help guys!
 
A 4 Drive RAID 1 is massive overkill, but it can spit out some nice IOPS if done correctly.
 
Yeah the read IOPS of 4 drives, with the write IOPS of one drive.

Not quite ideal setup, but still a nice performing setup for write once read many file usage, with many small reads.
 
If there was anything I would suggest if the guy wanted to go that path would be a 6 drive array of 2 striped 3 drive mirrors.

Some really nice read IOPS, and enough write IOPS to saturate gigE in both directions.
 
staticlag, that is one thing i like about raid10 with zfs. 3x2 array, so my random IOPS is 6 spindles. not all software or hardware raid does read load balancing though.
 
You must log in or register to reply here.
Back
Top