Upgrading to Dell Poweredge T440 - Raid 1 + Raid 5 Help HDs
My small business is getting a Dell Poweredge T440 and we were advised to use Raid 1 for the OS and Raid 5 for the other drives.
We are going to get 8, 3.5 inch slots for HDs. OS will use 2 drives and Raid 1. Then we want 4 drives to be set up with Raid 5.
Does this give us 4 drives and 2 "hot spares"?
We are going to get 8, 3.5 inch slots for HDs. OS will use 2 drives and Raid 1. Then we want 4 drives to be set up with Raid 5.
Does this give us 4 drives and 2 "hot spares"?
What PERC (Dell Array controller) was purchased with the server?
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H730P
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You might want to consider using RAID 6 instead of RAID 5
2 raid 1 for OS Space based on 1 disk
5 DISKS for RAID 6 Space is 3xsize of disk
1 global hot spare.
Though a spinning drive even if not accessed can go bad, it might be better to have the one drive on hand and not in the system unless and until you get a warning that a drive is having issued.
Without knowing for what purpose the system is being setup,
2 raid 1 for OS Space based on 1 disk
5 DISKS for RAID 6 Space is 3xsize of disk
1 global hot spare.
Though a spinning drive even if not accessed can go bad, it might be better to have the one drive on hand and not in the system unless and until you get a warning that a drive is having issued.
Without knowing for what purpose the system is being setup,
ASKER
Thanks for the information guys. I realized I was off in my initial post. I want a net of 4 Drives so with RAID 5 I would need 5 drives (4 net drives, 1 parity). This would leave me with 1 "hot spare".
If I configured this with RAID 6 would that mean in order to get 4 net drives I would need to have 6 drives setup for RAID 6 (4 net, 2 parity)? Would this option effectively leave me with no "hot spares"?
If I configured this with RAID 6 would that mean in order to get 4 net drives I would need to have 6 drives setup for RAID 6 (4 net, 2 parity)? Would this option effectively leave me with no "hot spares"?
Correct RAID 6 requires to 2 parity discs, RAID 6 can tolerate 2 drive failures. I prefer a hot spare and alerting.
ASKER
Thanks again for helping me wrap my head around RAID 1+ RAID 5 / RAID 6
Dell no longer consider RAID 5 as suitable for Enterprise Computing!
go with RAID 6.
go with RAID 6.
What size drives are we talking about?
Raid 5 rebuild following a drive failure takes a while depending on the drive size, during that time a se obj drive failure (due to higher load) would bring down the array.
A performance hit is significant.
What will be residing on the raid 5 volume?
https://www.zdnet.com/article/why-raid-5-still-works-usually/
https://www.zdnet.com/article/why-raid-5-still-works-usually/
Raid 5 rebuild following a drive failure takes a while depending on the drive size, during that time a se obj drive failure (due to higher load) would bring down the array.
A performance hit is significant.
What will be residing on the raid 5 volume?
https://www.zdnet.com/article/why-raid-5-still-works-usually/
https://www.zdnet.com/article/why-raid-5-still-works-usually/
SFF chassis may make more sense, then you get 16 drive bays rather than 8. Of course you can't have huge capacity drives but it's those high capacity drives that you really do need RAID 6 for. Only costs about €50 to get 8 extra bays*. The low capacity 3.5 inch ones are 2.5 inch anyway internally, e.g. "2.4TB 10K RPM SAS 12Gbps 512e 2.5in Hot-plug Hard Drive, 3.5in HYB CARR " from the customize it option on Dell's site.
*plus the cost of the extra disk.
*plus the cost of the extra disk.
I would if supported go with a global hot spare and take the other "spare drive " and add it to the raid 5 disk.