[CentOS] storage for mailserver

Wed Sep 16 16:27:28 UTC 2020
Mark (Netbook) <mrw at mwcltd.co.uk>

Hi Michael,

With SSD's, no matter what storage technology is used, you pay your money 
and you take your choice.

The more expensive SSD's have higher I/O rates, higher data bandwidth and 
better durability.

I would go for NVMe as this gives a higher data rate with PCIe 3.0 and PCIe 
4.0 (twice the data rate) ones are just coming in to the market.

I believe that traditional Raid 5 and 6 are not required for SSD's

I have configured all my customer SSD subsystems for Raid 1 (mirror), 
reduced overhead.

Cost defines if the above is acceptable.

Also, do you use hardware or software Raid 1.

There are many other questions but the above is a start.

Mark Woolfson
MW Consultancy Ltd
LS18 4LY
United Kingdom
Tel: +44 113 259 1204
Mob: +44 786 065 2778
-----Original Message----- 
From: Michael Schumacher
Sent: Wednesday, September 16, 2020 5:11 PM
To: CentOS mailing list
Subject: [CentOS] storage for mailserver


I am planning to replace my old CentOS 6 mail server soon. Most details
are quite obvious and do not need to be changed, but the old system
was running on spinning discs and this is certainly not the best
option for todays mail servers.

With spinning discs, HW-RAID6 was the way to go to increase reliability
and speed.
Today, I get the feeling, that traditional RAID is not the best
option for SSDs. I am reading that all RAID members in SSD-arrays age
synchronously so that the risk of a massive failure of more than one
disk is more likely than with HDDs. There are many other concerns like
excessive write load compared to non-raid systems, etc.

Is there any common sense what disk layout should be used these days?

I have been looking for some kind of master-slave system, where the
(one or many) SSD is taking all writes and reads, but the slave HDD
runs in parallel as a backup system like in a RAID1 system. Is there
any such system?

Any thoughts?

best regards
Michael Schumacher

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