Hi, On Monday 13 February 2012 16:15:16 Jeff Wiegley wrote: > In other words... GlusterFS TRIPLES all my storage costs to provide > 2 brick fault tolerance? > How do I get redundancy in GlusterFS while getting reasonable > storage costs where I am not wasting 50% of my investment or > more in providing copies to obtain redundancy? Show me any kind of redundancy without multiplying the efforts! Take a simple raid1 with two disks: How do you achieve fault-tolerance against one failing drive without storing the data on a second disk? When you need tolerance against two failing disks (at the same time), you have to have at least three disks containing the data. For bigger setups there are raid-levels that work with more then two disks and are tolerant against one or two failed drives, but then you "loose" one or two disks in your array for checksums. And these have a lot of disadvantages too. As cheap as disk-space got the last years (save the last 4 months since the flood), most admins just use raid1 and be done with it. (Yes, I am an advocate of baarf, though not an "official member":) Now the problem with raid inside one machine is that you still have the single-point-of-failure of motherboard, cpu, memory, psu(*), controller and network(to a point). With systems like glusterfs, moosefs, drbd and others you have your raid span multiple machines removing these spofs while preserving the advantage of local disk-reads. When you use the fs that way... And on a side-note: I don't know what you get per hour but taking low it-wages in germany it takes probably less then one man-week of data-recovery to amortize the "investment" of doubling disks and machine for redundancy. And when the data is lost due to missing redundancy, its not only one persons work that is lost... The additional hardware pays off faster then your boss/client can think about the expenses. Have fun, Arnold (*) Yes, you can have multiple psu in one machine. And thats nice too when you switch your machine from one ups to another. But power is still distributed by one power-distribution-board. Which is why I count the psu still as a spof. -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 198 bytes Desc: This is a digitally signed message part. URL: <http://gluster.org/pipermail/gluster-users/attachments/20120214/f27f703a/attachment.pgp>
