RAID for backup. RAID 5 or RAID 1?

RAID for backup. RAID 5 or RAID 1?

Post by Marshall L » Tue, 12 Apr 2005 16:02:42


I am contemplating adding some hard disks for backing up my SBS2003 server.
Should I go for RAID 5 or RAID 1?
Any consensus here? The array will be used ONLY for backup and restore
purposes and nothing else.

Any insight will be much appreciated.

Marshall
 
 
 

RAID for backup. RAID 5 or RAID 1?

Post by Matt Gibso » Tue, 12 Apr 2005 16:15:14

Either or.

RAID 1 provides the cheapest solution, but in the unlikely event you lose
both disks at once, you're hosed.

RAID 5 proves a more expensive solution, but if you include a hot spare (4
drives total), then you can lose up to 2 drives (just not at once)

If it's only for backup, I'd do RAID 1, but then again, I don't avocate
backing up to hard drives.

Matt Gibson - GSEC

 
 
 

RAID for backup. RAID 5 or RAID 1?

Post by Marshall L » Tue, 12 Apr 2005 16:45:42

Yes but in terms of percentage-wise, both RAID 1 and RAID 5 can sustain up
to 50% hardware failure. But RAID 5 will need a hot spare. How about
performance-wise?

This is a home server (yup. using some heavy duty equipment to just serve
myself and family) so hard disks as backup media will do.........
 
 
 

RAID for backup. RAID 5 or RAID 1?

Post by Matt Gibso » Tue, 12 Apr 2005 17:06:54

Well, RAID 1 offers no improvement in write performance, but doubles your
read performance. In other words, won't give you any improvment in backup
speeds.

RAID 5 on the other hand offers faster write speeds than a single drive, and
VERY high read speeds.

If you're looking for perfomance, go with RAID 5.

Matt Gibson - GSEC
 
 
 

RAID for backup. RAID 5 or RAID 1?

Post by Marshall L » Tue, 12 Apr 2005 17:21:17

Are you sure? I thought the XOR operation for RAID 5 is taxing on system
performance? I am planning to implementing this on the limited equipment
(an SI 3114 controller) which probably does not have hardware accelerated
RAID5........

In any case, for cost reasons, I will probably go with a pair of 160G SATA
on RAID 1. A side question, should I use the RAID 1 capability with the
SI3114 chipset or should I go with SBS2003's managed RAID 1?

I will probably g
 
 
 

RAID for backup. RAID 5 or RAID 1?

Post by Matt Gibso » Tue, 12 Apr 2005 18:05:35

ere's where you get into the "it depends" answers.

Yes, if you try and do RAID 5 in software, you basically lose all
performance increases.

If you do it with a NICE RAID controller card however, it's nice and speedy.

I'm not sure about that SI model, but I've used an SI controller for a 4
drive RAID 5 array before, and it wasn't bad at all.

I'd always!! use the hardware controllers over software based RAID.
Software RAID is icky.

Matt Gibson - GSEC


"Marshall Lai" < XXXX@XXXXX.COM > wrote in message
news: XXXX@XXXXX.COM ...


 
 
 

RAID for backup. RAID 5 or RAID 1?

Post by Marshall L » Tue, 12 Apr 2005 19:40:27

ut the SI is not real hardware RAID..... Even the website states software
RAID..... Ah well....
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RAID for backup. RAID 5 or RAID 1?

Post by Mark » Tue, 12 Apr 2005 22:15:31

RAID has NEVER and WILL NEVER be a form of BACKUP!
 
 
 

RAID for backup. RAID 5 or RAID 1?

Post by Marshall L » Wed, 13 Apr 2005 00:15:12

Maybe I am not clear or maybe you are not clear. I have a system up and
running. The array will be used for MS Backup only. So maybe what you are
saying is technically true (RAID is not a form of backup as in itself, just
redundancy), the use of the array is for backup purpose.......

This is for home and I will not and cannot afford an off-site backup........
 
 
 

RAID for backup. RAID 5 or RAID 1?

Post by SuperGumby » Wed, 13 Apr 2005 11:59:51

look, you're both being clear, but you're missing each other's view.

Mark, Marshall intends to use the RAID array as the medium on which his
backup is stored. Does that make everyone happy? (except me, I prefer tape)
 
 
 

RAID for backup. RAID 5 or RAID 1?

Post by Marshall L » Wed, 13 Apr 2005 12:42:28

OK. I get your point. But what you are saying can equally apply to where
you are storing your NON-RAID backup media..... Also, what about an
off-site backup which is using RAID to mirror your data? Would you consider
that backup? For some firms that I work with, they use some EMC disks
located offsite for backup and guess what, they are in some sort of RAID
(mirror or stripping with parity of course).

I do thankyou for pointing out the possible failure of using on-site RAID as
a backup policy. And I DO (believe it or not) understand your point and you
do have one. But the safety of the backup is not only the medium one use
and how the backup are stored. And even if I store them on tape or dvds,
they are still susceptible to fire hazard or theft if I don't store them
securely. And personally, I think that is a bit overkill for a home
user..... But that's just me.:)

And for data, I do care but now my data (pictures, bills, email, videos, and
other junks) are duplicated (and synchronized) on my workstation, my laptop,
and my server and I am adding another dedicated backup medium. I think
that's good enough for my casual use........
 
 
 

RAID for backup. RAID 5 or RAID 1?

Post by R29kZnJleS » Wed, 13 Apr 2005 13:06:05

Marshall:

Another possibility you might want to consider is to back up onto an
external USB drive. It is a cheap, very fast option. I use it

Godfrey
 
 
 

RAID for backup. RAID 5 or RAID 1?

Post by Les Connor » Wed, 13 Apr 2005 13:39:40

Sure, or even an internal IDE drive in this case.

--
Les Connor [SBS Community Member - SBS MVP]
-----------------------------------------------------------
SBS Rocks !
 
 
 

RAID for backup. RAID 5 or RAID 1?

Post by Marshall L » Wed, 13 Apr 2005 15:53:39

Thanks for the suggestion. Thought of that before but performance probably
is a bit slower then internal harddisks.
Except if you are talking about 3.5" external enclosures of course. But
then those things are very bulky. Not to mention there is no
redundancy......
 
 
 

RAID for backup. RAID 5 or RAID 1?

Post by Marshall L » Wed, 13 Apr 2005 15:54:17

Thanks. That's what I am thinking about except that I would also want
redundancy on the backup drive......
"Les Connor [SBS Community Member - SBS MVP]" < XXXX@XXXXX.COM >