Why I chose Equallogic over NetApp
I recently had to buy some more storage for our virtualized XenServer cluster at work and just wanted to comment on how I believe NetApp have shot themselves in the foot when it comes to SMBs. I don't usually post such techie stuff, but this really annoyed me.
We currently run an older entry level NetApp FAS250 box. Its a single controller model with 14x300Gb FC disks in it and I can say it is one of the most reliable things on our network, although performance isn't incredible.
So I went to upgrade and wittled the choices down to boxes with comparible pricing: the NetApp FAS2020 (12x1TB SATA disks) and Equallogic PS5000E (16x750GB disks), both with dual controllers.
Here is a big problem with NetApp I found:
You cannot create RAID groups over 8TB on the NetApp. In addition to this, on a dual controller setup you need at least two aggregates anyway.
So, on a one box filer you not only lose a massive amount of space but also, as the more spindles you have in a RAID group the higher the performance, you lose that too!
Compare the two standard setups and see the difference:
NetApp FAS2020: 1x Five Disk RAID-DP, 1x Six Disk RAID-DP, 1x hot spare ~7TB raw space (1TB disks).
Equallogic PS5000E: 1x Fourteen disk RAID 10, 2x hot spares. ~ 5.25TB raw space (750GB disks) or 1x 15 disk RAID 50, 1x hot spare. ~7.5TB raw space.
RAID 10 is probably going to be faster than RAID DP anyway, so add the extra spindles and it should be MUCH faster than the NetApp box. Does anyone from NetApp want to comment on these stupid restrictions? I'll report more when my box arrives and tell you about the performance.
We currently run an older entry level NetApp FAS250 box. Its a single controller model with 14x300Gb FC disks in it and I can say it is one of the most reliable things on our network, although performance isn't incredible.
So I went to upgrade and wittled the choices down to boxes with comparible pricing: the NetApp FAS2020 (12x1TB SATA disks) and Equallogic PS5000E (16x750GB disks), both with dual controllers.
Here is a big problem with NetApp I found:
You cannot create RAID groups over 8TB on the NetApp. In addition to this, on a dual controller setup you need at least two aggregates anyway.
So, on a one box filer you not only lose a massive amount of space but also, as the more spindles you have in a RAID group the higher the performance, you lose that too!
Compare the two standard setups and see the difference:
NetApp FAS2020: 1x Five Disk RAID-DP, 1x Six Disk RAID-DP, 1x hot spare ~7TB raw space (1TB disks).
Equallogic PS5000E: 1x Fourteen disk RAID 10, 2x hot spares. ~ 5.25TB raw space (750GB disks) or 1x 15 disk RAID 50, 1x hot spare. ~7.5TB raw space.
RAID 10 is probably going to be faster than RAID DP anyway, so add the extra spindles and it should be MUCH faster than the NetApp box. Does anyone from NetApp want to comment on these stupid restrictions? I'll report more when my box arrives and tell you about the performance.
Labels: equallogic, netapp, storage
posted by James White at 10:27 AM
5 Comments:
With comparing performance of the EQ implementation of RAID 10 to the NetApp RAID DP, I would have to say performance is pretty much a match. In some areas the EQ seems slightly ahead, such generic file copy and move tasks, but for exchange DP seems to be a bit ahead.
If the SAN isn't going to be expanded, then the RAID 10 solution is a good one, but the disk penalty after expansion seems to favour RAID DP, and if your decision is based on performance, you will be implementing storage based on smaller sized disk and more spindles as a whole. RAID 10 will really start to hurt you going down that track.
For a single shelf solution with SATA disks, I would take the cheaper FAS2020 solution personally. Who knows, the 8TB limit might be a software update and away you go...
This post has been removed by the author.
Just an amendment to my earlier comment, as an option you could always go with a NetApp configuration along these lines as it turns out the 7.3.x release does give you larger raw aggregate sizes:
Upgrade to 7.3.x (16TB RAW limit for aggregates!)
RAID4 aggr0 (root) - 2 disks )one data/one parity)
RAIDDP aggr1 (rest of your storage) - 9 disks (7 data, 1 parity, 1 DP)
SPARE - 1 disk
That should net you some decent storage allocation and keeps the root aggr0 to a nice and small and hence quick rebuild.
Things to keep in mind (netapp gotchas):
1. Hotspare configuration:
options raid.min_spare_count 1
- to set just the one hot spare (Note that netapp recommends a minimum of 2 hot spares, but I think on a single shelf system you could justify a single spare)
2. Use the CLI and not the GUI to assign disks to the aggr1 - the GUI doesn't always allow to add that final last 1 or 2 disks for some reason. The CLI works everytime.
aggr add aggr1 x@ yyy
- where x is the number of disks and yyy is the size. I think 828 or something similar if you are using 1TB sata disk.
**edit - forgot to mention, obviously the RAID4 is potentially at risk from a lower level of protection than RAID DP - I think from memory, the root vol is only really around 12GB in size as a rule of thumb, so you could always copy this to the other aggr1 as backup.
"For a single shelf solution with SATA disks, I would take the cheaper FAS2020 solution personally."
If you factor in the fact that you have to pay for all the software licences on top, NetApp is far more expensive. (Snapshots, Exchange/SQL integration etc..).
"
Upgrade to 7.3.x (16TB RAW limit for aggregates!)
RAID4 aggr0 (root) - 2 disks )one data/one parity)
RAIDDP aggr1 (rest of your storage) - 9 disks (7 data, 1 parity, 1 DP)
SPARE - 1 disk"
Great, but with EqualLogic you don't lose 2 disks to the root partition. You can use the whole load of disks in one storage pool, again with the speed advantage of more spindles.
Oh, lets also not forget that controllers on NetApp can't share an aggregate, so again you need two aggregates on a dual controller box anyway. Again, Equallogic wins.
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