Sun Storage 7410 space calculator
The Sun Storage 7410 is our expandable storage appliance that can be hooked up to anywhere from one and twelve JBODs with 24 1TB disks. With all those disks we provide the several different options for how to arrange them into your storage pool: double-parity RAID-Z, wide-strip double-parity RAID-Z, mirror, striped, and single-parity RAID-Z with narrow stripes. Each of these options has a different mix of availability, performance, and capacity that are described both in the UI and in the installation documentation. With the wide array of supported configurations, it can be hard to know how much usable space each will support.
To address this, I wrote a python script that presents a hypothetical hardware configuration to an appliance and reports back the available options. We use the logic on the appliance itself to ensure that the results are completely accurate as the same algorithms would be applied as when then the physical pallet of hardware shows up. This, of course, requires you to have an appliance available to query — fortunately, you can run a virtual instance of the appliance on your laptop.
You can download the sizecalc.py here; you'll need python installed on the system where you run it. Note that the script uses XML-RPC to interact with the appliance, and consequently it relies on unstable interfaces that are subject to change. Others are welcome to interact with the appliance at the XML-RPC layer, but note that it's unstable and unsupported. If you're interested in scripting the appliance, take a look at Bryan's recent post. Feel free to post comments here if you have questions, but there's no support for the script, implied, explicit, unofficial or otherwise.
Running the script by itself produces a usage help message:
$ ./sizecalc.py
usage: ./sizecalc.py [ -h <half jbod count> ] <appliance name or address>
<root password> <jbod count>
Remember that you need a Sun Storage 7000 appliance (even a virtual one) to execute the capacity calculation. In this case, I'll specify a physical appliance running in our lab, and I'll start with a single JBOD (note that I've redacted the root password, but of course you'll need to type in the actual root password for your appliance):
$ ./sizecalc.py catfish ***** 1
type NSPF width spares data drives capacity (TB)
raidz2 False 11 2 22 18
raidz2 wide False 23 1 23 21
mirror False 2 2 22 11
stripe False 0 0 24 24
raidz1 False 4 4 20 15
Note that with only one JBOD no configurations support NSPF (No Single Point of Failure) since that one JBOD is always a single point of failure. If we go up to three JBODs, we'll see that we have a few more options:
$ ./sizecalc.py catfish ***** 3
type NSPF width spares data drives capacity (TB)
raidz2 False 13 7 65 55
raidz2 True 6 6 66 44
raidz2 wide False 34 4 68 64
raidz2 wide True 6 6 66 44
mirror False 2 4 68 34
mirror True 2 4 68 34
stripe False 0 0 72 72
raidz1 False 4 4 68 51
In this case we have to give up a bunch of capacity in order to attain NSPF. Now let's look at the largest configuration we support today with twelve JBODs:
$ ./sizecalc.py catfish ***** 12
type NSPF width spares data drives capacity (TB)
raidz2 False 14 8 280 240
raidz2 True 14 8 280 240
raidz2 wide False 47 6 282 270
raidz2 wide True 20 8 280 252
mirror False 2 4 284 142
mirror True 2 4 284 142
stripe False 0 0 288 288
raidz1 False 4 4 284 213
raidz1 True 4 4 284 213
The size calculator also allows you to model a system with Logzilla devices, write-optimized flash devices that form a key part of the Hybrid Storage Pool. After you specify the number of JBODs in the configuration, you can include a list of how many Logzillas are in each JBOD. For example, the following invocation models twelve JBODs with four Logzillas in the first 2 JBODs:
$ ./sizecalc.py catfish ***** 12 4 4
type NSPF width spares data drives capacity (TB)
raidz2 False 13 7 273 231
raidz2 True 13 7 273 231
raidz2 wide False 55 5 275 265
raidz2 wide True 23 4 276 252
mirror False 2 4 276 138
mirror True 2 4 276 138
stripe False 0 0 280 280
raidz1 False 4 4 276 207
raidz1 True 4 4 276 207
A very common area of confusion has been how to size Sun Storage 7410 systems, and the relationship between the physical storage and the delivered capacity. I hope that this little tool will help to answer those questions. A side benefit should be still more interest in the virtual version of the appliance — a subject I've been meaning to post about so stay tuned.
Update December 14, 2008: A couple of folks requested that the script allow for modeling half-JBOD allocations because the 7410 allows you to split JBODs between heads in a cluster. To accommodate this, I've added a \-h option that takes as its parameter the number of half JBODs. For example:
$ ./sizecalc.py -h 12 192.168.18.134 ***** 0
type NSPF width spares data drives capacity (TB)
raidz2 False 14 4 140 120
raidz2 True 14 4 140 120
raidz2 wide False 35 4 140 132
raidz2 wide True 20 4 140 126
mirror False 2 4 140 70
mirror True 2 4 140 70
stripe False 0 0 144 144
raidz1 False 4 4 140 105
raidz1 True 4 4 140 105
Update February 4, 2009: Ryan Matthews and I collaborated on a new version of the size calculator that now lists the raw space available in TB (decimal as quoted by drive manufacturers for example) as well as the usable space in TiB (binary as reported by many system tools). The latter also takes account of the sliver (1/64th) reserved by ZFS:
$ ./sizecalc.py 192.168.18.134 ***** 12
type NSPF width spares data drives raw (TB) usable (TiB)
raidz2 False 14 8 280 240.00 214.87
raidz2 True 14 8 280 240.00 214.87
raidz2 wide False 47 6 282 270.00 241.73
raidz2 wide True 20 8 280 252.00 225.61
mirror False 2 4 284 142.00 127.13
mirror True 2 4 284 142.00 127.13
stripe False 0 0 288 288.00 257.84
raidz1 False 4 4 284 213.00 190.70
raidz1 True 4 4 284 213.00 190.70
Update June 17, 2009: Ryan Matthews with help from has again revised the size calculator to model both adding expansion JBODs and to account for the now expandable Sun Storage 7210. Take a look at Ryan's post for usage information. Here's an example of the output:
$ ./sizecalc.py 172.16.131.131 *** 1 h1 add 1 h add 1
Sun Storage 7000 Size Calculator Version 2009.Q2
type NSPF width spares data drives raw (TB) usable (TiB)
mirror False 2 5 42 21.00 18.80
raidz1 False 4 11 36 27.00 24.17
raidz2 False 10-11 4 43 35.00 31.33
raidz2 wide False 10-23 3 44 38.00 34.02
stripe False 0 0 47 47.00 42.08
Update September 16, 2009: Ryan Matthews updated the size calculator for the 2009.Q3 release. The update includes the new triple-parity RAID wide stripe and three-way mirror profiles:
$ ./sizecalc.py boga *** 4
Sun Storage 7000 Size Calculator Version 2009.Q3
type NSPF width spares data drives raw (TB) usable (TiB)
mirror False 2 4 92 46.00 41.18
mirror True 2 4 92 46.00 41.18
mirror3 False 3 6 90 30.00 26.86
mirror3 True 3 6 90 30.00 26.86
raidz1 False 4 4 92 69.00 61.77
raidz1 True 4 4 92 69.00 61.77
raidz2 False 13 5 91 77.00 68.94
raidz2 True 8 8 88 66.00 59.09
raidz2 wide False 46 4 92 88.00 78.78
raidz2 wide True 8 8 88 66.00 59.09
raidz3 wide False 46 4 92 86.00 76.99
raidz3 wide True 11 8 88 64.00 57.30
stripe False 0 0 96 96.00 85.95
** As of 2009.Q3, the raidz2 wide profile has been deprecated.
** New configurations should use the raidz3 wide profile.