Postgres Pro
Downloads
Home   >   mailing lists

Thread: dissimilar drives in Raid10 , does it make difference ?

dissimilar drives in Raid10 , does it make difference ?

From
Rajesh Kumar Mallah
Date:
I have received Dell Poweredge 2950 MIII with 2 kind of
drives. I cant' make out the reason behind it , does it
make any difference in long run or in performance
the drives are similar in overall characteristics but does
the minor differences if will cause any problem ?

scsi0 : LSI Logic SAS based MegaRAID driver
  Vendor: SEAGATE   Model: ST973451SS        Rev: SM04
  Type:   Direct-Access                      ANSI SCSI revision: 05
  Vendor: FUJITSU   Model: MBC2073RC         Rev: D506
  Type:   Direct-Access                      ANSI SCSI revision: 05
  Vendor: FUJITSU   Model: MBC2073RC         Rev: D506
  Type:   Direct-Access                      ANSI SCSI revision: 05
  Vendor: SEAGATE   Model: ST973451SS        Rev: SM04
  Type:   Direct-Access                      ANSI SCSI revision: 05
  Vendor: SEAGATE   Model: ST973451SS        Rev: SM04
  Type:   Direct-Access                      ANSI SCSI revision: 05
  Vendor: FUJITSU   Model: MBC2073RC         Rev: D506
  Type:   Direct-Access                      ANSI SCSI revision: 05
  Vendor: SEAGATE   Model: ST973451SS        Rev: SM04
  Type:   Direct-Access                      ANSI SCSI revision: 05
  Vendor: FUJITSU   Model: MBC2073RC         Rev: D506
  Type:   Direct-Access                      ANSI SCSI revision: 05

thanks
regds
-- mallah

Re: dissimilar drives in Raid10 , does it make difference ?

From
Matthew Wakeling
Date:
On Fri, 13 Feb 2009, Rajesh Kumar Mallah wrote:
> I have received Dell Poweredge 2950 MIII with 2 kind of
> drives. I cant' make out the reason behind it , does it
> make any difference in long run or in performance
> the drives are similar in overall characteristics but does
> the minor differences if will cause any problem ?

As long as the drives are approximately the same capacity and speed, then
no, it will not cause problems.

In fact, it is recommended that two different types of drives are used.
That way, if there's a mass failure of a whole batch of drives from one
particular vendor, you don't lose all your data.

Matthew

--
"Programming today is a race between software engineers striving to build
 bigger and better idiot-proof programs, and the Universe trying to produce
 bigger and better idiots. So far, the Universe is winning."  -- Rich Cook

Re: dissimilar drives in Raid10 , does it make difference ?

From
Craig Ringer
Date:
Matthew Wakeling wrote:

> In fact, it is recommended that two different types of drives are used.
> That way, if there's a mass failure of a whole batch of drives from one
> particular vendor, you don't lose all your data.

Don't think this is just paranoia, either. I've had it happen to me
SEVERAL times - either a second drive fails before I can replace the
first, or the second drive in a pair fails during rebuild onto the
replacement. I use regular RAID scrubbing, so this isn't just a case of
undetected media errors.

Nothing beats good backups.

--
Craig Ringer