Miscellaneous - My reference

• 25MW DC can run around 50000 servers => 25000:50000 => 1KW=2servers 1 server with 500 Watts but DC PUE of 1 that is not possible in Middle East. In Middle East 25MW DC can power more or less around 20000 server
• DCIM
• Hotspot in DC identification. Some capable of creating CFD to find hotspot
• Power capacity available, used and forecast of power requirement
•  Locate and inventory of assets like Rack, IT - Network devices, cooling, ups. Require the DCIM process need to be followed as assets are placed and deployed in DC
• Maximize uptime by generating alerts and reporting predictive failures.
• OpenDCIM(free sofware), Sunbird, Struxware, Sunird, Equinix IBX SmartView
• TCP and UDP  both are layer 4 protocol of OSI Model.  TCP is connection oriented, ack packet delivery and hence slow but reliable while UDP is connection-less and doesnot ack packet delivery and hence fast.
• Layer 2 - Data link deals with MAC and Layer 3 consist of IP/ARP capable of routing
• Docker container enable to create multiple container that share same kernel/OS and faster to deploy multiple container on single system. Kubernetes is orchestration engine that can be used to deploy multiple docker container
• VMware HA enable the VM to start on another node of the cluster in case actual node on which VM running fails. Distributed Resource Scheduling enable the movement of VMs among the cluster nodes depending on the load on each node.  VMs can be moved using vMotion from heavily utilized nodes to less utilized nodes.
• For normal operations core is vCPU ration is 1:4 it can be 1:1 or 1:2 for high performance requirement.
• In case customer has around 1000 systems/storage  and wants to move to hyper converged or some sort of tech refrsh then given details should be collected
• Performance
• Total cores and Total frequency vs utilized cores and utilized frequency 
• Total Memory vs utilized memory 
• Total storage vs allocated storage vs used storage, rate of storage efficiency like compression, deduplication, compaction, Raid/Erasure Code/Redundancy factor, replication factor used for data and metadata. 
• Latency IOPS and Throughput for local storage and networked shared storage 
• Network throughput, type of network Ethernet 1gb/10gb/25gb/40gb copper/fiber, FC 8/16/32gb
• Tools that can be utilized liveoptics, onCommand insight, HP Openview, Solarwinds
• Tick-Tock should be Tock-Tick as micro architecture change is Tock and then process to shrink processor that is Tick. Bride(sandy, ivy)-> well(hash,broad)->lake(sky, copper, tiger, meteor)

S3 bucket can be mounted on EC2 instance as filesystem known as s3fs. s3fs is a fuse(file system in user space) file system that enables mounting of S3 on local filesystem.
#sudo yum update all
#sudo yum install automake fuse fuse-devel gcc-c++ git libcurl-devel libxml2-devel make openssl-devel
#git clone https://github.com/s3fs-fuse/s3fs-fuse.git (clone s3fs source code from git)
# cd s3fs-fuse
# ./autogen.sh
#./configure --prfix=/usr  --with=openssl
#make
#sudo make install
#which s3fs
authentication require access key and secret access key
#cat >  /etc/passwd-s3fs
#accesskey:secretkey
#sudo chmod 640 /etc/passwd-s3fs
#mkdir /mys3bucket
#s3fs vijayraj -o use_cache=/tmp -o allow_other -o uid=1001 -o mp_umask=002 -o multireq_max=5 /mys3bucket
make etries in rc.local
#vi /etc/rc.local
/usr/bin/s3fs your_bucketname -o use_cache=/tmp -o allow_other -o uid=1001 -o mp_umask=002 -o multireq_max=5 /mys3bucket


Multipath

systemctl start multipathd.service
systemctl enable multipathd.service
/sbin/mpathconf --enable --user_friendly_names y
systemctl start multipathd
Multipath -ll

# multipath -ll
mpatha (3600a098000f78555000000e65d47e35f) dm-3 NETAPP  ,INF-01-00
size=400T features='4 queue_if_no_path pg_init_retries 50 retain_attached_hw_handle' hwhandler='1 alua' wp=rw
|-+- policy='service-time 0' prio=50 status=active
| `- 7:0:0:0 sdb     8:16  active ready running
`-+- policy='service-time 0' prio=10 status=enabled
  `- 7:0:1:0 sdd     8:48  active ready running


[root@xxxxx ~]# mkfs.xfs /dev/mapper/mpatha


# mkdir -p /dat02_share
# chown nfsnobody:nfsnobody /dat02_share

# mount /dev/mapper/mpatha /dat02_share


# systemctl start nfs
firewall-cmd --permanent --zone=public --add-service=nfs
firewall-cmd --reload

iptables -I INPUT -j ACCEPT
iptables -I OUTPUT -j ACCEPT

iptables -I INPUT -p tcp --dport 80 -j ACCEPT -m comment --comment "Allow HTTP"
iptables -I INPUT -p tcp --dport 443 -j ACCEPT -m comment --comment "Allow HTTPS"
iptables -I INPUT -p tcp -m state --state NEW --dport 22 -j ACCEPT -m comment --comment "Allow SSH"
iptables -I INPUT -p tcp --dport 8071:8079 -j ACCEPT -m comment --comment "Allow torrents"

iptables -A INPUT -i lo -j ACCEPT -m comment --comment "Allow all loopback traffic"
iptables -A INPUT ! -i lo -d 127.0.0.0/8 -j REJECT -m comment --comment "Drop all traffic to 127 that doesn't use lo"
iptables -A OUTPUT -j ACCEPT -m comment --comment "Accept all outgoing"
iptables -A INPUT -j ACCEPT -m comment --comment "Accept all incoming"
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT -m comment --comment "Allow all incoming on established connections"
iptables -A INPUT -j REJECT -m comment --comment "Reject all incoming"
iptables -A FORWARD -j REJECT -m comment --comment "Reject all forwarded"




Bye...