hardware raid 5 over raid 10

[thomaslally]

Disk space is not a concern, performance and above all failover
capacity are more important to us. I've seen plenty of posts about
RAID 5 and RAID 10 (1 + 0)

But, the people (such as silver Dell tech support)I was asking to are
mostly suggesting me to use RAID 5, especially HARDWARE RAID 5 with hot
spare which is not that slow compared to RAID 10, even for writing.
What do you think?

Thanks

Thomas

 

[Peter E. Fry]

Disk space is not a concern, performance and above all failover
capacity are more important to us. I've seen plenty of posts about
RAID 5 and RAID 10 (1 + 0)

But, the people (such as silver Dell tech support)I was asking to are
mostly suggesting me to use RAID 5, especially HARDWARE RAID 5 with hot
spare which is not that slow compared to RAID 10, even for writing.
What do you think?

You need relatively impressive hardware for your RAID 5 to outperform
your stripe and mirror. But if resilience is paramount, why not
mirrored RAID 5? Some SCSI RAID controllers could do it, back when I
used 'em.
For the most part writes are (or at least should be) hidden by the
system and controller caches, so I tend to look at read performance.
Oh, and the age-old question: "How fast do you want to spend?"

Peter E. Fry

 

[thomaslally]

not that fast I'm affraid... but thanks Peter for the advice. My
primary concern is about safety, reliability. performance comes after.
Thomas

 

[thomaslally]

not that fast I'm affraid... but thanks Peter for the advice. My
primary concern is about safety, reliability. performance comes after.
Thomas

 

[Rick]

not that fast I'm affraid... but thanks Peter for the advice. My
primary concern is about safety, reliability. performance comes after.

Based on what I see in the field, my opinion is this: given the
reliability of today's hard drives, and given that 9 out of every 10
system failures today are not related to drive failure (errant drivers
or driver upgrades, software patches and updates, virus infection
etc etc), the simple fact is RAID5 and similar fault tolerant
solutions don't provide much and in most cases any protection.

Corporations are abandoning RAID5 and moving to periodic
offline mirroring, where systems are backed up in their entirety
every night or periodically during the day. This not only protects
against drive failure but also against software issues that cause
the vast majority of system failures.