> We also have 4-disk nodes, and we use the following layout: > 2 x OS + Commit in RAID 1 > 2 x Data disk in RAID 0 +1
You are replicating data at the application level and want the fastest possible IO performance per node. > You can already distribute the > individual Cassandra column families on different drives by just > setting up symlinks to the individual folders. There are some features coming in 1.2 that make using a JBOD setup easier. Cheers ----------------- Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 30/10/2012, at 9:23 PM, Pieter Callewaert <pieter.callewa...@be-mobile.be> wrote: > We also have 4-disk nodes, and we use the following layout: > 2 x OS + Commit in RAID 1 > 2 x Data disk in RAID 0 > > This gives us the advantage we never have to reinstall the node when a drive > crashes. > > Kind regards, > Pieter > > > From: Ran User [mailto:ranuse...@gmail.com] > Sent: dinsdag 30 oktober 2012 4:33 > To: user@cassandra.apache.org > Subject: Re: idea drive layout - 4 drives + RAID question > > Have you considered running RAID 10 for the data drives to improve MTBF? > > On one hand Cassandra is handling redundancy issues, on the other hand, > reducing the frequency of dealing with failed nodes is attractive if cheap > (switching RAID levels to 10). > > We have no experience with software RAID (have always used hardware raid with > BBU). I'm assuming software RAID 1 or 10 (the mirroring part) is inherently > reliable (perhaps minus some edge case). > > On Tue, Oct 30, 2012 at 1:07 AM, Tupshin Harper <tups...@tupshin.com> wrote: > I would generally recommend 1 drive for OS and commit log and 3 drive raid 0 > for data. The raid does give you good performance benefit, and it can be > convenient to have the OS on a side drive for configuration ease and better > MTBF. > > -Tupshin > > On Oct 29, 2012 8:56 PM, "Ran User" <ranuse...@gmail.com> wrote: > I was hoping to achieve approx. 2x IO (write and read) performance via RAID 0 > (by accepting a higher MTBF). > > Do believe the performance gains of RAID0 are much lower and/or are not worth > it vs the increased server failure rate? > > From my understanding, RAID 10 would achieve the read performance benefits of > RAID 0, but not the write benefits. I'm also considering RAID 10 to maximize > server IO performance. > > Currently, we're working with 1 CF. > > > Thank you > > On Mon, Oct 29, 2012 at 11:51 PM, Timmy Turner <timm.t...@gmail.com> wrote: > I'm not sure whether the raid 0 gets you anything other than headaches > should one of the drives fail. You can already distribute the > individual Cassandra column families on different drives by just > setting up symlinks to the individual folders. > > 2012/10/30 Ran User <ranuse...@gmail.com>: > > For a server with 4 drive slots only, I'm thinking: > > > > either: > > > > - OS (1 drive) > > - Commit Log (1 drive) > > - Data (2 drives, software raid 0) > > > > vs > > > > - OS + Data (3 drives, software raid 0) > > - Commit Log (1 drive) > > > > or something else? > > > > also, if I can spare the wasted storage, would RAID 10 for cassandra data > > improve read performance and have no effect on write performance? > > > > Thank you! >
