On Sat, May 16, 2009 at 12:08 AM, Maurice Hilarius <maurice@xxxxxxxxxxxx> wrote: > SandeepKsinha wrote: > > .. > > RAID 4 vs RAID 5 > Actually debatable. They have their own pros and cons and especially > where you don't consider the physical properties of disk. > Addition of new disk, differences in speed of disks, etc.. create > bottlenecks especially in case of RAID5. > > Except hot spot issue with RAID 4, I find it better than all others. > Also, most of the proprietary solutions from IBM, Adaptec and NetApp > suggest RAID4 as compared to others. > > No offenses please, this is just an opinion. > > > In a lot of uses, RAID4 is actually preferable. > Putting all parity data on one disk allows us to "cheat" and use a faster > drive for that parity disk. > Thus we can gain some performance over RAID5 or 6. > > To avoid the risk factor increase, we can use a more reliable AND faster > disk/interface for that parity device. > > For reads we gain a fair bit of performance by doing this. > > Further, we may "cheat" by using a single larger parity disk. > By doing so, if we add more data disks, we still have reserve space for > growth on the larger parity disk. > > Yes, our write rates are lousy, but for some uses this is OK. > Yes, rebuilds are slow too.. > What makes you think that the rebuilds are slower? > > > -- > With our best regards, > > Maurice W. Hilarius Telephone: 01-780-456-9771 > Hard Data Ltd. FAX: 01-780-456-9772 > 11060 - 166 Avenue email:maurice@xxxxxxxxxxxx > Edmonton, AB, Canada T5X 1Y3 -- Regards, Sandeep. “To learn is to change. Education is a process that changes the learner.” -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
