Re: Software vs. Hardware RAID 1

Dances With Crows <danSPANceswitTRAPhcrows@xxxxxxxxx> wrote in
news:slrneb5vkk.fcs.danSPANceswitTRAPhcrows@xxxxxxxxxxxxxxxxxxxxxxxxxxx:

["Followup-To:" header set to comp.os.linux.hardware.]
On 10 Jul 2006 23:57:22 GMT, x0054 staggered into the Black Sun and
said:
2 HD bays which I intend to fill with 2 ATA100 250GB drives. The
motherboard has 2 ATA133/100 IDE [channels]. If I go with Software
RAID1 I would have HD1 as master on the primary IDE bus and HD2 as
master on [the] secondary IDE bus, with the CD drive as slave on the
same bus.

What I am wondering is how software RAID1 [compares] with HW RAID1
and if there are any significant advantages or drawbacks to either.

SoftRAID-1 will probably be *faster* than doing RAID in hardware.
Hardware RAID generally uses a fairly slow dedicated bit of silicon.
SoftRAID uses the main CPU, which is A) damn fast and B) usually idle
in a modern machine. The main problem is that softRAID is a bit less
transparent than hardware RAID. Just read the RAID HOWTO and you'll
be fine. Also remember that you'll probably need to copy the first 63
sectors of /dev/hda to /dev/hdc manually with dd, since softRAID
doesn't mirror the bootloader, just the partitions.

Also, is it a problem that HD2 will share [an] IDE [channel] with my
CD drive? I [am] only really going to use the CD drive to install
linux.

This shouldn't matter on a modern board, so long as you're not using
the CD-R* much. Only one device per IDE channel can be active at
once, thanks to IDE's designed-in brain damage, so your softRAID won't
be fully R while your CD-R* is running. HTH,


Thanks, that sounds great. Yeah, actually I probably would disconnect
the CD-ROM after install all together. Really the only reason for it is
to load Debian.

I looked though SW RAID setup, and it looks very straight foreword. The
one other question I had had to do with booting. You mentioned that I
would need to copy over, or maybe install, bootloader on both drives.
When setting up bootloader would I tell it to boot from hda or hdc, or
can I specify md0 (the SW raid disk)?

If I specify the actual disk I would have to change it respective to the
disk. Right? So on hda the bootloader would be set to boot from hda and
on hdc it would be set to hdc?

Thanks again for the help,

- Bogdan
.

Relevant Pages

  • Re: [SLE] 3ware sata controllers info
    ... > the past few years but never have used one of the sata raid controllers. ... > I'm thinking that I'm having a speed problem with ide 3ware raid an want to ... I'm sure you know the 3ware ide RAID cards masqarade as SCSI cards. ...
    (SuSE)
  • RE: my first raid disaster on reboot :o( update
    ... including swap are raid1 and they boot and mount fine now. ... Subject: my first raid disaster on reboot:o(update ... > its corrupt superblock or ext2 file system complaints. ...
    (Debian-User)
  • Re: Is RAID worth it?
    ... as RAID0 (there are also two other HDD's for data/storage set as RAID1), then I read a thread from within this newsgroup in which Carey Frisch directed someone to read - Why RAID is a Terrible Idea http://www.pugetsystems.com/articles?&id=29 and that has made me re-think my plans. ... Is RAID really worth? ... Indeed my own experience of a previous PC with RAID1 showed that it was by no means an easy task to restore everything when one HDD did fail after just 4 months. ... The one think that RAID1 'was' in my mind always useful for was data protection so I'm thinking there must be a way whereby I can install all four drives so that only two are visible and the other two are a mirror image set so that at the end of the day, or maybe twice a day, some software would back up the main visible drives to the 'invisible' back-up drives. ...
    (microsoft.public.windows.vista.installation_setup)
  • =?ISO-8859-1?Q?Re=3A_=5Bfixed=5D_re-enabling_RAID1_on_?= =?ISO-8859-1?Q?existing
    ... I have 2 SATA HDs in my machine that were working as RAID1 earlier. ... So I fiddled around in the BIOS, and decided, in my endless wisdom, to change my SATA from IDE to RAID. ... but my drivers for RAID (Intel® Matrix Storage) are totally gone. ... And I am glad my BIOS reports my drives now on SATA controller as RAID. ...
    (microsoft.public.windowsxp.hardware)
  • Re: RAID 1 with IDE HDD
    ... >i am new to the RAID installation and functioning. ... >Both the HDD are connected to the same IDE cable as master and salve. ... simply because with a RAID-1 array of two IDE drives a failure ... image stored on a RAID array, and there is no advantage to doing ...
    (comp.os.linux.misc)