Contents
What type of RAID’s can be created with ZFS?
stripe
mirror
n-way mirror
raidz or raidz1
raidz2
Size and Speed of the different RAID-types
Info
These information I’ve got from: WHEN TO (AND NOT TO) USE RAID-Z
| St | = | Total size of the pool |
| n | = | Number of disks in the pool |
| Sdisk | = | Size of one Disk |
| vf | = | Speed Factor (1 = Same speed as a single Disk) |
| vdisk | = | Speed of the disk is Blocks/Seconds |
| x | = | Number of Stripes |
Stripe
You stripe all disks together:
St = n * Sdisk
vf = n
Example: Assume we have 100 Disks 50GB each which can write 200 Blocks/seconds:
Total RAID size...: 5000 GB = 100 Disk * 50 GB/Disk Speed factor......: 100 = 100
Mirror
You mirror two disks or two stripe-sets:
St = (n / 2 ) * Sdisk
vf = n / 2
Example: Assume we have 100 Disks, 50GB each which can write 200 Blocks/seconds. We make the mirror over a stripesets of 50 Disk each:
Total RAID size...: 2500 GB = ( 100 Disk / 2 ) * 50 GB/Disk Speed factor......: 50 = 100 Disks / 2
raidz
You stripe some raidz’s:
St = (( n / x ) – 1 ) * Sdisk * x
vf = x
Example: Assume we have 100 Disks 50GB each which can write 200 Blocks/seconds and we stripe 5 raidz’s together:
Total RAID size...: 4750 GB = (( 100 Disk / 5 Stripes ) - 1 ) * 50 GB/Disk * 5 Stripes Speed factor......: 5 = 5