Re: Poor raid 1 performance?

> > Maybe, because how data is organized on each disk, it makes difficult to
> > stream (read sequentially) with full speed, while reading every other
> > sector?
>
> I'm not sure, but I don't think the data is organized much differently.
The
> two disks of a RAID1 (2 disk) array are supposed to have identical data.
So
> what hinders a RAID1 controller to read one stripe from disk A while
> reading another stripe from disk B (just like the same controller would do
> in a RAID0 configuration)? It also could do head movement optimization,
> like using one disk for reading the disk index and the other disk for
> reading the data (or more elaborate schemes to minimize head movement).
> From what people wrote here, the RAID controllers don't seem to do this
> with RAID1. Anybody knows why not?

It is organized very differently. There are NO STRIPES in RAID1. On each
disk data seem to be organized exactly the same as on standalone hard drive.


.

Relevant Pages

  • [fwd] md raid1 chokes when one disk is removed
    ... (Was hoping to ask RedHat ... I like to give my system a bit of added resiliency with RAID1. ... Here's a capture of my Disk Druid: ... unused devices: ...
    (Fedora)
  • md raid1 chokes when one disk is removed
    ... Our boxes are SuperMicro 6018HT with dual SATA drives. ... I like to give my system a bit of added resiliency with RAID1. ... Here's a capture of my Disk Druid: ... unused devices: ...
    (RedHat)
  • Re: Poor raid 1 performance?
    ... >>> you have the data in stripes over several disks. ... With RAID1, you have ... >> Maybe, because how data is organized on each disk, it makes difficult to ... > while reading another stripe from disk B (just like the same controller ...
    (comp.sys.ibm.pc.hardware.storage)
  • Re: Strange boot-time hang (long, sorry)
    ... root FS on a software RAID1 array and the served files ... Several days ago, this machine crashed, probably due to a disk ... Why did the machine crash due to a disk failure if its on a raid1 ...
    (Debian-User)
  • Re: [ANNOUNCE] Ramback: faster than a speeding bullet
    ... to the ramdisk at some point, and you cannot just read from the ramdisk ... Wouldn't a raid-1 set comprising disk + ramdisk do that with no downtime? ... In raid1, write completion has to wait for write completion on all ... This is very close to how ramback already works. ...
    (Linux-Kernel)