ausip's questions

In the Exchange 2016 preferred architecture recommendations put out by Microsoft. The recommendation is for JBOD storage for information stores. I understand the basis of the recommendation and the semantics of recovery etc. but I am trying to get clarification on Microsoft's definition of JBOD.

In the RAID controller world, JBOD can be defined as a bunch of disks bundled together and displayed as one drive. ie: no RAID level, concatenated to make one large volume.

I am assuming that Microsoft's definition is displaying each individual disk to the OS as an individual volume.

Thoughts please...

Microsoft's - The Preferred Architecture

We are building up some new servers and want to use 12Gbps SAS3 drives alongside some SATA 6Gbps Enterprise SSD's attached to a single Supermicro SAS3 backplane using an LSI SAS3 Expander and LSI / Broadcom 9361-8i RAID Controller with CacheCade Pro 2.0.

RAID Config will be as follows

• Array 1: 2 x SATA3 SSDs RAID1
• Array 2: 2 x SATA3 SSDs RAID1
• Array 3: 6 x SAS3 HDDs RAID10
• CacheCade Pro 2.0 attached to Array 3: 2 x SATA3 SSDs

Question 1: Will 12Gbps and 6Gbps drives play nicely on the same 12gpbs expander and controller without compromising performance?

Question 2: Should I use interposers on the SATA3 SSDs to achieve the RAID config outlined above?

We have just setup a recursive DNS server using the latest stable release of Bind 9.10

We are finding that recursive DNS lookups are quite slow. Anywhere from 1 - 3 seconds. Once the lookup is in cache, DNS resolves in a matter of milliseconds as expected.

We are utilising ROOT hints for the recursive lookups and this seems to be where the slowness is coming from. If we configure a forwarder the DNS resolution comes down to a sensible recursion time of 100 - 300ms.

For the service we are setting up, I don't want to rely on forwarders, I would prefer to use root hints.

Here is the main config from our named.conf file. Any pointers to help improving the performance would be great.

options{
allow-recursion  { any; };
allow-query-cache  { any; };
allow-query  { any; };

listen-on  port 53  { any; };
listen-on-v6  port 53  { any; };

dnssec-enable yes;
dnssec-validation yes;
dnssec-lookaside auto;

zone-statistics yes;
max-cache-ttl 3600;
max-ncache-ttl 3600;

/* Path to ISC DLV key */
bindkeys-file "/etc/named.iscdlv.key";
managed-keys-directory "/var/named/dynamic";

directory  "/var/named";
dump-file  "/var/named/data/cache_dump.db";
statistics-file  "/var/named/stats/named_stats.txt";
memstatistics-file  "/var/named/stats/named_mem_stats.txt";

rate-limit {
    responses-per-second 10;
    log-only yes;
};

prefetch 5;};

zone "." {
type hint;
file "named.ca";};

include "/var/named/conf/logging.conf";