Hello, I made some more research on this topic.
I am thinking of a solution using linux software RAID for disk crash. RAID 1 seems the best solution for this. (am I right?) It works with disk mirroring. This means that the data is in fact duplicated and written to both disks. This of course sets a high load on the CPU and the data buses. So my question is: In practical terms, suppose we have 2 common 200 GB SATA-II disks (7200 RPM) buffer size 8MB, and about 8-10 ms average seek time for read/write (Or something like that). And suppose we have a 1GB RAM , on x86 (not 64 bit) with about 3GHZ CPU clock. And suppose we are NOT talking about servers but of a common linux programmer environment. (But on which a disk crash is unbearable and there is management which may afford another disk for that withouth hesitating). Will it be bearable to use such a solution ? Or will the machine be so slow that it will be unbearable ? I simply cannot test Linux RAID 1 performance because it invloves erasing data and formattin to create a RAID set. So if anyone have experience with Linux RAID-1, he is welcomed to respond. RG On 9/2/06, Gilboa Davara <[EMAIL PROTECTED]> wrote:
On Sat, 2006-09-02 at 10:53 +0300, Rafi Gordon wrote: > Hi Gilboa , > > Thanks for your qeustion. > > I had encountered chapter 26 , which is devoted to linux software raid ,in > "Linux(r) Quick Fix Notebook" book By Peter Harrison. > (Published by Prentice Hall.) > Here is a quote grom the end of this chapter: > > CONCLUSION > Linux software RAID provides redundancy across partitions and hard disks, > but it tends to be slower and less reliable than RAID provided by a > hardwarebased > RAID disk controller. > > > No advantage what-so-ever > > So when you say "No advantage what-so-ever" ,are you referring only when > comparing linux raid software to chip IDE RAID cards ? or is your > opinion different than Peter Harrison, the book author ? > > Regards, > R. Gordon In my previous workplace we did extensive benchmarks between a 3ware 9xxx 8-port SATA RAID controller and software RAID using the Intel ICH and in general, the 3ware was indeed faster (and much more expensive). However, under certain workloads the software RAID outperformed it and as we replaced the CPUs from Nocoma Xeons to AMD Opteorns, the performance gap decrease considerably. In short, if you afford an expensive SATA/IDE raid, it -should- perform better then the kernel software RAID. If you want to spend less then 400 $ on a (new) RAID controller, don't bother, it'll perform much slower then the Linux' software RAID. * * As long as you have a reasonably fast (P4 > 2Ghz, AMD > 1.4Ghz) machine and enough memory. Gilboa ================================================================= To unsubscribe, send mail to [EMAIL PROTECTED] with the word "unsubscribe" in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
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