atacontrol software or hardware raid

2009-01-25 Thread Omer Faruk Sen
How can I detect if system has Software or hardware raid? Since in manual page:

 The atacontrol command can also be used to create purely software RAID
 arrays in systems that do NOT have a real hardware RAID card such as a
 Highpoint or Promise card.  A common scenario is a 1U server such as the
 HP DL320 G4 or G5.  These servers contain a SATA controller that has 2
 channels that can contain 2 disks per channel, but the servers are wired
 to only place a single SATA drive on each channel.

Or how can I find out if the hardware is real hardware RAID card?
For example my system has following dmesg output:

ad4: 152627MB Seagate ST3160815AS 4.AAB at ata2-master SATA300
ad6: 152627MB Seagate ST3160815AS 4.AAB at ata3-master SATA300
ar0: 152625MB Intel MatrixRAID RAID1 status: READY
ar0: disk0 READY (master) using ad6 at ata3-master
ar0: disk1 READY (mirror) using ad4 at ata2-master

This system is an intel server with S3210SH server board in it. While
installing system I see ad4,ad6 and ar0 as harddrives in sysinstall. I
choose to install ar0.

Additionally as far as I see ar0 is very susceptible to errors since a
single CRC error can break the RAID consistency is that normal?  I
really appreciate those who uses such a kind of RAID1

Regards.
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Re: atacontrol software or hardware raid

2009-01-25 Thread Josh Paetzel
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Hash: SHA1

Omer Faruk Sen wrote:
 How can I detect if system has Software or hardware raid? Since in manual 
 page:
 
  The atacontrol command can also be used to create purely software RAID
  arrays in systems that do NOT have a real hardware RAID card such as a
  Highpoint or Promise card.  A common scenario is a 1U server such as the
  HP DL320 G4 or G5.  These servers contain a SATA controller that has 2
  channels that can contain 2 disks per channel, but the servers are wired
  to only place a single SATA drive on each channel.
 
 Or how can I find out if the hardware is real hardware RAID card?
 For example my system has following dmesg output:
 
 ad4: 152627MB Seagate ST3160815AS 4.AAB at ata2-master SATA300
 ad6: 152627MB Seagate ST3160815AS 4.AAB at ata3-master SATA300
 ar0: 152625MB Intel MatrixRAID RAID1 status: READY
 ar0: disk0 READY (master) using ad6 at ata3-master
 ar0: disk1 READY (mirror) using ad4 at ata2-master
 
 This system is an intel server with S3210SH server board in it. While
 installing system I see ad4,ad6 and ar0 as harddrives in sysinstall. I
 choose to install ar0.
 
 Additionally as far as I see ar0 is very susceptible to errors since a
 single CRC error can break the RAID consistency is that normal?  I
 really appreciate those who uses such a kind of RAID1
 
 Regards.
 ___
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ar RAID devices are almost always software/BIOS RAID.  In this case
intel matrix raid is software RAID provided by the system BIOS.  The
disadvantages of using it is your RAID array isn't portable to machines
that don't have the same BIOS raid implimentation.

One of the advantages of BIOS RAID is that you can boot from stripes,
which you aren't doing anyways.

You'll probably find that disabling the motherboard RAID and creating a
gmirror device is a better option for software RAID 1.

- --
Thanks,

Josh Paetzel

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Re: atacontrol software or hardware raid

2009-01-25 Thread Josh Paetzel
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Hash: SHA1

Omer Faruk Sen wrote:
 How can I detect if system has Software or hardware raid? Since in manual 
 page:
 
  The atacontrol command can also be used to create purely software RAID
  arrays in systems that do NOT have a real hardware RAID card such as a
  Highpoint or Promise card.  A common scenario is a 1U server such as the
  HP DL320 G4 or G5.  These servers contain a SATA controller that has 2
  channels that can contain 2 disks per channel, but the servers are wired
  to only place a single SATA drive on each channel.
 
 Or how can I find out if the hardware is real hardware RAID card?
 For example my system has following dmesg output:
 
 ad4: 152627MB Seagate ST3160815AS 4.AAB at ata2-master SATA300
 ad6: 152627MB Seagate ST3160815AS 4.AAB at ata3-master SATA300
 ar0: 152625MB Intel MatrixRAID RAID1 status: READY
 ar0: disk0 READY (master) using ad6 at ata3-master
 ar0: disk1 READY (mirror) using ad4 at ata2-master
 
 This system is an intel server with S3210SH server board in it. While
 installing system I see ad4,ad6 and ar0 as harddrives in sysinstall. I
 choose to install ar0.
 
 Additionally as far as I see ar0 is very susceptible to errors since a
 single CRC error can break the RAID consistency is that normal?  I
 really appreciate those who uses such a kind of RAID1
 
 Regards.
 ___
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 http://lists.freebsd.org/mailman/listinfo/freebsd-questions
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ar RAID devices are almost always software/BIOS RAID.  In this case
intel matrix raid is software RAID provided by the system BIOS.  The
disadvantages of using it is your RAID array isn't portable to machines
that don't have the same BIOS raid implimentation.

One of the advantages of BIOS RAID is that you can boot from stripes,
which you aren't doing anyways.

You'll probably find that disabling the motherboard RAID and creating a
gmirror device is a better option for software RAID 1.

- --
Thanks,

Josh Paetzel

PGP: 8A48 EF36 5E9F 4EDA 5ABC 11B4 26F9 01F1 27AF AECB
-BEGIN PGP SIGNATURE-
Version: GnuPG v1.4.8 (Darwin)

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kn8An27y/SPbEKzRyaWntfZV95z/UJia
=k2Gx
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Re: atacontrol software or hardware raid

2009-01-25 Thread Wojciech Puchar


ar RAID devices are almost always software/BIOS RAID.  In this case
intel matrix raid is software RAID provided by the system BIOS.  The


it's always better to use gmirror. not mentioning more flexibility (you do 
not have to mirror whole drives)

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