Every Storage Admin Must and Should Know This

MY NOTES

• HBA Company – Emulex, Q- logic
• Switches – Brocade, CISCO
• SAN Surface is used to manage the Brocade switch.
• Cisco is managed by HBA anywhere / OCM (one command manager)
• Zoning – Connecting initiator node and target node.
• ALIAS – nick names for WWNs.
• How we login into switch: Telnet & SSH are used to login into switch.
• MDS – Cisco
• B-Series – Brocade
• Cisco Fabric manager, EMC san manager & device manager are the management tools for switch.
• Adding a LUN to Multiple storage group is not recommended configuration because this will allow multiple hosts to have simultaneous access to LUN.
• DMX Features – Non Disruptive upgrade, Multi site disaster recovery, enterprise consistent.
• In DMX each storage bay consists of 240 drives.
• CMI is used to setup the Management IP.
• Domain: Combining all the storages under one roof to manage.
• Thin LUNs: On-Demand Storage Allocation.
• Thick LUNs: Fully allocated at the time of creation.
• Minimum No of disks: 3 (Raid-5), 4(Raid-6), 3 or 9 (Raid-3)
• Raid Group Limit to 16 Disks.
• Raid-6: accept even number of disks, defragment is not allowed.
• How to access LUNs: kept LUN in storage group, assign HOST to SG.
• CLI (command line interface) used for Configure, Manage and Monitor Blades.
• Proactive Hot Spare: Replacement of a drive without operating in degraded mode.
• Information and Error Msg are logged in Ktrace or event logs.
• Replication Manager: Manage and automate snapshots and clone for various replication product. Ex: Microsoft Exchange and SQL server Volumes.
• Recovery Point CDP: It maintain a history journal of all changes that can be used to roll back the mirrors to any point in time.
• SanpSure: Create Checkpoint , view file system
• SanpView:  To view the File System, Point in Time Copies of LUNs.
• Types of Tickets (BMC Ready S/W):        Incident – Which are not planned.

                                                                           Change – Which are planned.

                                                                           Problem – Happen in sudden or any disaster.

• FAST: Fully Automated Storage Tire (FC-Fast, SAS-Medium speed, SATA - Least): Moving the most active data to costly or expensive disk (for performance) & less active data to low cost disk. It can also use pool storage system.

CMDs: >>”storage”>>”pool”>>R.C “Pool 0”>>”properties”>>S “Tiering” Tab.

               >>Pools>>R.C “Pool 0”>> S “Strat active”.

• CORE EDGE:      CORE Connected to Storage.

                              EDGE connected to Host.

• DMX Architecture: Front End, Cache, Back End, Disks.
• Hyper is a Slick, One part of physical disk.
• Selera                  Operating Systems – DART
• Clariion                              Operating Systems – FLARE.

                              CMD Line – San Copy.

                              GUI – Navisphere.

• VNX                      Operating Systems - VNX OE.

                              CMD Line – Naviseccli.

                              GUI – Unisphere.

• Symmentrix      Operating Systems – Eingunity.

                              CMD Line – Symcli.

                              GUI – SMC (Symmentrix Management Console).

• SLA: Service level Agreement
• Fiber, GIGE, ISCON are Open System interface.
• ESCON & FICON are mainframe interface.
• Hardware & Microcode (73,74,75,76)      

               52 – Symm4

               53 – Symm5

               56 – DMX 1 / 2 (5672)

               57 – DMX 3 / 4 (5773)

               58 – VMAX (5874, 5875, 5876)

• Diff B/W Vmax SE & Vmax: Vmax SE Cannot Expanadable, Performance & availability.

                                                  Vmax Can Expandable, Scalability.

• Vmax has 8 Engines – each engine has 2 directories – each directories has 128 FE ports.

Each System Bay has – 3 Stand-by-power supply + 1 UPS (uninterrupted power supply).

Operation Layer:    L1: Symm based app, host-based app, and independent app.

                                   L2: EMC Solution Enabler API.

                                   L3: Symm Enginuity Operating Environment.

                                   L4: Symm hardware.

• Read Hit: Requested data in the Global memory.
• Read Miss: Requested data not in Global memory and retrieved from disk Device.
• Fast Write: The Channel directory store the data in Global Memory and sends “Channel End” and “Device End” to the host.
• Delayed Fast Write: Disconnect the Channel director from the channels, when sufficient global memory space is available, then the channel director re-connect to their channels and process the I/O request as Fast Write.
• Symm Service Processor is used to manage IMPL.BIN File.
• Dynamic Sparing (Spare Disk): Protection of all volumes from loss of data.
• Local Replication: Time finder / Clone / Snap /and mirror.
• Tiering: Tiering is the process of grouping the disks based on their size, speed and Technology (Tier consisting of 1TB SATA or 400GB FC 10K Disks) 
• Journaling: Used to speed up the processor.
• SCSi: used to connect certain devices with limitation.
• Vault Disk: First four disks in a 1^st Enclosure, it contain OS
• D-Stage: when right cmd id given, where power failure occurs.
• Clar Alert: It is used to notify Emc people about error occurs in system.
• Sniff Verify: Low Priority Check.
• Back-ground Check: High Priority Check, cannot be interrupted, manually operated.
• SPOF: Single point of failure.
• CMI: Clariion message Interface
• Hot Spare: Backup disk, When disk failure occurs
• Flushing Right Cache: To maintain free cache pages are flushed are moved to the right cache to the disk.
• Three types of flushing:   Ideal Flushing,

                                             Watermark flushing,

                                             Force Flushing.

• User Quota Restriction: Limiting the disks blocks for a particular users.
• San Copy: used to transfer vnx to 3^rd party storage.
• Access Logic: Masking & Mapping.
• ALUA: Assessment logical unit access.
• Power Path: manage active-passive from host side, multi pathing and load balance.
• CIFS: File Format in windows.

NFS: Unix or Linux.

• Quorum Drive: It is used to store the info about which drive is active or not used in windows.
• SMART GRIP: It is used for all meter reading from all the applications.
• NPIV: Node Port ID Virtualization, it is FC facility, it allows N port to connect virtually to a single physical port.
• When power Failure occurs, Data is moved to Vault Drive.
• Data Duplication: If two servers are accessing came data.
• NP Backup: taking backup into a tape drive.
• SymmWin is in symmentrix service processor.
• Solution Enabler 7.0 and higher running on the symmentrix Vmax.
• We can run up to 4 concurrent configuration changes session at the same time.

·        Default Stripe Size is 1920

·        What is Concatenating & Stripped?

Concatenating - First byte of data at the beginning of the first device and addressing continues to the end of the first device before any data on the next device is referenced.

Stripping - divides the data to a series of stripes.

• Once we dissolve the Meta, we will never get that data back.
• What is the cmd to Drain the pool cmd: rebalance.
• DR: Disaster Recovery.

IE: implementation engineer.

CE: customer Engineer.

• SHIFT + CTRL + F12: To open engineer mode.
• VIO generates Virtual WWN.
• We can pick a least used FA port from Performance Monitor.
• Explain Rule 17 in DMX: The Rule of 17 is to make sure that redundancy is in place so that the host does not lose access in case of a FA/DA director failure. The director cage of DMX can have
  16 director cards numbering from 1-16. Two director cards are paired in such a way that the total adds up to 17. Example when a host is connected/ lun is mapped
  to the FA it is mapped to directors 1 and 16 or to directors 10 and 7.

·        How do you calculate number of cylinders for 50GB LUN?
A cylinder is roughly 1 mb in size and 0.937mb to be precise

               15 tracks -1 cylinder

64 blocks – 1 track

512 bytes-1 block

1024= conversion of bytes to kb to mb to GB

GB=cylinder *15*128*512/1024/1024/1024-DMX3 DMX4 VMAX

GB=cylinder *15*64*512/1024/1024/1024 -DMX DMX2

• What is the maximum hyper size in DMX-4?
  60Gb and in case of Vmax 240Gb
• How many hypers can create in a Single disk?
  255 and in case of Vmax 512

• How many members can contain in one Meta?
  Max 255 members
• How many LUN IDs available per port?
  Technically speaking 2048. Per port pair 4096, however this is flexible meaning either one can have all the 4096 devices or 2048 each or any combination which does not exceed 4096. However this is not a good practice.
• What Dynamic LUN addressing?
  Once the lun id on the port crosses 255 the host will not be able to see the lun and hence lun offset has to be used which has to be implemented carefully if not would lead to host losing access to devices (luns). In order to overcome this dynamic lun addressing is used in which the luns are numbered in the ascending order to the Host HBA
• How do you add a new member to the existing Meta?
  using the add  command
  symconfigure –sid 1234 –cmd “add dev X to meta Y”; commit

·        Briefly explain the DMX-4 supported Device types?

               Mainframe and Open systems devices

• What are the DMX-4 supported disk types, no. of disks and maximum capacity?
  FC, SATA. SSD supported. Capacity and number of disks vary from configuration to configuration.
• What are the RAID levels DMX-4 Supports?
  RAID 0 - unprotected
  RAID 1 - 2-way Mirror
  RAID 5
  RAID 6
  RAID 1 / 0 - 2 way Mirror Meta (Striped).
• What is Preview, Prepare and Commit while using Symconfigure command?
  Preview - verifies the command syntax
  Prepare - ensured that sufficient system resources are available and also checks for any existing locks
  Commit- commits the configuration. This can be run directly as it performs both the Preview and prepare actions as well.

·        How do you check the failed disks in the Symmetrix Array?

               symdisk -sid 2258 -failed list

• What are the service states of a device?
  RW
  NR
  Write_disabled
• How do you reserve the devices?
  symconfigure –sid 4042 reserve dev 0667
• How do you check the free space by Disk group and Array as whole?
  symconfigure list -freespace or more accurate is symdisk list -dskgrp_summary

·        How many Cache directors, Front-end directors and Back-end directors we can use in DMX-4?

               Cache directors -8

               Front-end directors -8

               Back-end directors -8

·        What are the different types of Front-end directors and the purpose of each one?

               Mainframe CKD devices:

                              ESCON (EA)

                              FICON (EF)

               Open Systems FBA

                              Fibre channel (FA)

                              ISCSI (SE)  etc

·        What are the Management Tools for DMX?

               EMC Control Center (ECC)

               SMC

               EMC Solutions Enabler

               EMC Symmetrix Performance Analyzer

·        What are the major components of System Bay and Storage Bay?

               System Bay:

                              Directors and Memory boards, FANS, KVM, SPS, UPS, Power Supplies, XCM boards

               Storage Bay

                              DAEs, BBU (Battery Backup Unit), SPS, LCC Link control card

• Can windows, Linux, Solaris share the same FA in DMX?             ANS: YES
• Host is unable to see the storage, what may be the problem?

               Host WWN issue, Zoning issue, switch port failure, connectivity issue, SAN disk issue

• What is VCMDB and how do you take the backup?
  The Symmetrix Volume Configuration Management (VCM) database stores access configurations that are used to grant host access to logical devices in a Symmetrix storage array. The VCM database resides on a special system resource logical device, referred to as the VCMDB device, on each Symmetrix storage array.
  Information stored in the VCM database includes, but is not limited to:
• Host and storage World Wide Names.
• SID Lock and Volume Visibility settings.
•  Native logical device data, such as the front-end directors and storage ports to which they are  mapped Masking operations performed on Symmetrix storage devices result in modifications to the VCM database in the Symmetrix array. The VCM database can be backed up, restored, initialized and activated. The Symmetrix SDM Agent must be running in order to perform VCM database operations (except deleting backup files).

               Backup the VCM database

                     # symmaskdb backup

·        What are the Symmetrix Business Continuity Tool

               Time finder

               SRDF

·        By using what symcli command we can check the HBA details and physical details

               symmask list hba –list                    local host hba details

               symmask –sid  1234 –wwn           wwn list logins

               symmaskdb –sid 1234 –host         name list capcity (not in VMAX)

·        How do you list the Hosts which are connected to particular director port?

               symamsk –sid 1234 list logins –dir 10e  –p 1

·        How do you check the total allocated storage of a Host?

               Symmaskdb –sid 1234 –host name list capacity

·        What is the purpose of bin file in SAPAPI database?

               It contains the configuration information for a symmetrix. The file defines the

               Physical hardware configuration:

               -Directors

               -Memory

               -Physical Drives   

               Logical Storage configuration:

               Emulation, number, size and data protection schemes for logical volumes.

               Operational parameters and features:

               Located on each director and in SP

·        What is pre check list to assign to storage to the host?

               Host WWN details.

               Host and SAN connectivity to Fabric Switch

               Type of storage needed(Tier 1,Tier2 ,Tier3 )

               Size of the LUN

·        How do you check the login hosts in the Array?

               symmask –sid 1234 list logins

·        create a zone and place it in the vsan # zone name testzone1 vsan 4
add a member (port wwn example) # member pwwn 10:00:00:00:c9:21:40:b8 (port on the host)
add a member (fabric port wwn example) # member fwwn 10:01:10:01:10:ab:cd:ef (port on the switch)
add a member (FCID example - hard zoning) # member fcid 0x7f0000 (24 bit address)
add a member (FC alias example) # member fcalias payroll

·        MDS-series common commands
display logged in WWN, display vsan information # show flogi database
display the specific vsan logins # show fcns database vsan 4
activatng a zoneset # zoneset activate name zone1 vsan 4
delete a zoneset # clear zone dataabse vsan 4
configure the default zone # zone default-zone permit vsan 4
display zones and zonsets # show zoneset active
# show zoneset
# show zoneset active vsan 4
copy active zone set to the full zone set # zone copy active-zoneset full-zoneset vsan 4
distribute the full zoning database to others switches # zoneset distribute full vsan 4
==============================================================================
Creating zone by WWN

#zonecreate "zone1", "20:00:00:e0:69:40:07:08 ; 50:06:04:82:b8:90:c1:8d"
Create a zone configuration #cfgcreate "test_cfg", "zone1 ; zone2"
saving the zone configuration #cfgsave (this will save across reboots)
enable the zone configuration #cfgenable "test_cfg"
saving the zone configuration #cfgsave
view zoning information #zoneshow or cfgshow

If you want you can create alias for zone members as well with "alicreate" and use cfgadd command to add zones to the active configuration.

• DHCP provides the IP address to the computer.
• SYN packet – Communication Start.
• FIN packet – Communication End.

Time Finder: allows you to nondisruptively create and manage point-in-time copies of data. For example, Time Finder allows you to create a point-in-time copy of critical data while this data continues to be used in production operations.
TimeFinder

The TimeFinder family of software provides trusted local storage replication leveraging the high-end Symmetrix VMAX Architecture. The TimeFinder family enables IT organizations to create local copies for DR testing/validation, backups, point-in-time recovery, database consistency checks, and test/development. The TimeFinder family consists of the following options:

·        TimeFinder Clone – High performance, full source copies

·        TimeFinder Snap – Economical space saving copies

·        TimeFinder VP Snap – Space-efficient snaps for VP devices

Symmetrix Remote Data Facility (SRDF)

The SRDF family of software is the gold standard for remote replication in mission critical environments. Built for the industry-leading high-end VMAX hardware architecture, the SRDF family of solutions is trusted for disaster recovery and business continuity. The SRDF family offers unmatched deployment flexibility and massive scalability to deliver a wide range of distance replication capabilities. The SRDF family consists of the following options:

·        SRDF/S – Synchronous option for zero data exposure loss

·        SRDF/A – Asynchronous option for extended distances

·        SRDF/Star – Multi-site replication option

·        SRDF/CG – Consistency Groups for federated data sets across arrays

 

Migration to Symmetrix VMAX

VMAX customers have choice and flexibility for migrations in both open systems and mainframe environments. By enabling customers to perform migrations at the host or array level depending on their specific requirements, EMC offers the broadest set of migration options to help customers rapidly realize the performance and efficiency benefits of the VMAX family in the virtual data center. The migration options to migrate to the VMAX are as follows:

·        Open Replicator for Symmetrix – Heterogeneous, open-systems array-based migration

·        Federated Live Migration (FLM) – FLM using Open Replicator non-disruptively migrates workloads and redirects/hosts to the VMAX

·        z/OS Migrator – Non-disruptive migration for mainframe environments at the volume or dataset level

·        SRDF/DM – High performance Symmetrix to Symmetrix migration

·        Open Migrator – Host-based open systems data migration

 

Fully Automated Storage Tiering for Virtual Pools (FAST VP)

FAST VP automatically optimizes performance in a tiered environment reducing costs, footprint and management effort. FAST VP puts the right data in the right place at the right time. FAST VP maximizes utilization of Flash Drive capacity for high IOPS workloads and maximizes utilization of SATA drives for capacity intensive applications. FAST VP is a game changing technology that delivers automation and efficiency to the virtual data center.

 Points to Remember

• The software used to split physical disks into volumes is called Hyper Volume Extension.
• SymmWin software is used for modifying system configuration file (IMPL.bin).
• Symrdf --  command manages dynamic RDF operations
• symaccess -- manages masking and mapping operations on the VMAX
• symfast and symtier --  commands are responsible for managing FAST operations
• symmigrate -- manages virtual LUN migration.
• specific devices are “mapped” to specific ports by assigning a channel address. Host systems discover and access Symmetrix devices using these Channel Addresses.