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Storage
Storage Concepts
IP Storage: iSCSI and NAS/NFS
Fibre Channel SAN Storage
VMFS Datastores
Storage – virtual disks & VMFS
Storage Area Networks (SAN)
Understanding FC & iSCSI Storage
Why you need a SAN
Storage Ter...
Types of Storages
Local (SCSI/SATA/SAS/IDE)
SAN (Fibre Channel & iSCSI
NAS (NFS & CIFS)
Why do you need a Storage
ESX to Boot
For Virtual Machines
Centralized Storage is required for advanced features of vSpher...
ESX / ESXi
Incase if we choose to install ESX/ESXi Server, the Server can be
installed on the local disk of the physical m...
Space Requirements to Install ESX
vmkcore 110 Mb
boot Partition 1.1 Gb
/ root partition 5 Gb
var/log partition 2 Gb
swap p...
Space Requirements to Install ESX
So in all you need around 9.8Gb disk space is what you need maximum to
install ESX Serve...
What are all the ways to provide storage to the virtual machines?
When creating a virtual machine, you have options of Cre...
What is a Datastore?
A datastore is a logical storage unit that can use disk space on one physical device or
one disk part...
VMFS can be formatted with different block sizes which are defined while creating
datastores. For example a 2 TB Disk Form...
There is also no way to change the block size after you set it without deleting the
datastore and re-creating it, which wi...
RDM or Raw Device Mappings is a method of presenting a RAW LUN to a Virtual
Machine
RDM’s provide a way for Virtual Machin...
What Files Make Up a Virtual Machine?
VM Files
VMX file – The size of these files will be in KB’s
Log files, cannot grow more than MB’s
vmxd file, snapshot desc...
SAN (Storage Area Network)
SAN
Disks
Storage
Processor
(HBA)
HBA
ESX / ESXi
0 1
ESX / ESXi
0 1
FC Switch
Interconnecting M...
SAN (Storage Area Network)
Depending on the appropriate needs the SAN Administrator will create a
Hardware RAID and then c...
SAN (Storage Area Network)
SAN
Disks
Storage
Processor
(HBA)
HBA
ESX / ESXi
0 1
ESX / ESXi
0 1
FC Switch
Storage Group
WWN...
LUN Mapping & LUN Masking is done at the Storage End
SAN
Disks
Storage
Processor
(HBA)
HBA
ESX / ESXi
0 1
ESX / ESXi
0 1
F...
Identifying HBA’s
HBA are identied by vmhba, vmhba1 and so on.
Each and every HBA has a controller which is always 0
Disks...
Multipathing Policies
ESX / ESXi supports multipathing policies
NMT – Native Multipathing Polices which consists of
Fixed ...
Fibre Switch
Disks
Storage
Processor
(HBA)
HBA
ESX / ESXi
0 1
FC Switch
Storage Group
LUN1
T1 T2
For security a storage ad...
Zoning
Hard Zone
Is configured for the ports of the FC Switch
If a cable is plugged out from the zone port and attaches to...
What is the difference between a Fibre Channel and a iSCSI?.
Both are SAN
• iSCSI uses IP based connection
• Fibre Channel...
Understanding iSCSI Storage
iSCSI (Internet SCSI) is sending SCSI disk commands and data
over a TCP/IP network
Why use it?...
Understanding iSCSI Storage
Downside – performance? and reliability?
iSCSI Terms:
• iSCSI hardware initiator - a special i...
Disk Arrays
SP
Ethernet Switch
TCP/IP Network
ESX/ESXi
NIC
This can be a
NIC or iSCSI
HBA
iSCSI uses TCP/IP Protocol and u...
Understanding iSCSI Storage
iSCSI uses IQN (iSCSI qualified name) to identify iSCSI Targets &
Initiators
It is laid out in...
Understanding iSCSI Storage
Configuring iSCSI
Hardware Initiator (HBA)
Login to the iSCSI storage and reboot
Go to the bio...
Understanding iSCSI Storage
Configuring iSCSI
iSCSI uses 2 types of discovery method to connect to a iSCSI
storage
Static ...
Send Target (Dynamic)
Disk Arrays
SP
Ethernet Switch
TCP/IP Network
ESX/ESXi
NIC
Win2k
For Dynamic Discovery you need an a...
Send Target (Dynamic)
Lun Mapping and LUN Masking can be done at the iSCSI Storage System
These are done in 2 ways
On IP A...
NFS
NFS is supported by ESX/ESXi
CIFS is not supported at all
By default 8 NFS volumes can be mounted
This figure can be c...
NFS
NIC
Ethernet Switch
TCP/IP Network
ESX/ESXi
NIC
NFS is a file level access
Configured in /etc/exports
And then execute...
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Storage

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Storage

  1. 1. Storage Storage Concepts IP Storage: iSCSI and NAS/NFS Fibre Channel SAN Storage VMFS Datastores
  2. 2. Storage – virtual disks & VMFS Storage Area Networks (SAN) Understanding FC & iSCSI Storage Why you need a SAN Storage Terms you must know What is in a Datastore? ESX Server Storage Options VMFS Specs and Maxs Storage
  3. 3. Types of Storages Local (SCSI/SATA/SAS/IDE) SAN (Fibre Channel & iSCSI NAS (NFS & CIFS)
  4. 4. Why do you need a Storage ESX to Boot For Virtual Machines Centralized Storage is required for advanced features of vSphere like VMotion, VMHA, FT, and DRS
  5. 5. ESX / ESXi Incase if we choose to install ESX/ESXi Server, the Server can be installed on the local disk of the physical machine or on the SAN (Boot from SAN - Remote Boot). VMware ESX supports boot from SAN. Booting from SAN requires one dedicated LUN per server. VMware ESXi (4.1 Only) may be booted from SAN. This is supported for Fibre Channel SAN, as well as iSCSI and FCoE for certain storage adapters that have been qualified for this capability. (Refer HCL for supported Storage Adapters). ESXi comes in 2 version Embedded : The ESXi is embedded in the hardware on which there is a Flash ROM, these servers are mostly provided by vendors. Installable/ISO: ESXi is also available as Installable or an ISO
  6. 6. Space Requirements to Install ESX vmkcore 110 Mb boot Partition 1.1 Gb / root partition 5 Gb var/log partition 2 Gb swap partition 600 Mb to 1.6 Gb vmkcore partition is used to store the core dumps generated by the VMkernel. The /var/core directory is used to store the core dumps. Optionally you can go for Scratch Partition (Optionally) - We call it vFAT Scratch partition - 4Gb ESXi can locally boot from USB ROM, we may not have 4Gb on the USB Drive and we might not go for Vscratch partition. When we don't go for a Vscratch partition, ESXi Kernel additionally will use 512 Mb for itself, by default. VMkernel uses 154 Mb of memory plus incase you don't have a scratch partition, 512 Mb for itself. Vscratch partition is used for swap for the VMkernel. Swap is used for service console on ESX servers. It uses double or 1.5 times of the memory. Service Console uses minimum 300Mb minimum memory by default, so the Minimum swap partition is of 600Mb. Maximum memory it might use is 800 Mb, so swap should be allocated around 1.6Gb.
  7. 7. Space Requirements to Install ESX So in all you need around 9.8Gb disk space is what you need maximum to install ESX Server ESX Server supports upto 1 Tb of memory With regards to ESXi, it has a small footprint and it is possible to install ESXi 110/120 Mb ESXi can be installed on SCSI, SATA, IDE and SAN(ESXi 4.1). ESXi cannot boot NFS or CIFS. ESX can be booted from Fibre Channel SAN, 1st boot device would be FC HBA through which you are booting and the path to target storage processor between these two should be active path and not a passive path, and it should be able to recognize this boot LUN
  8. 8. What are all the ways to provide storage to the virtual machines? When creating a virtual machine, you have options of Create a new virtual disk, use existing virtual disk, use RDM or NO disk. What is the difference between a virtual disk and a raw disk For a operating system what is considered to be a raw?. A disk without a file system, without an operating system understandable file system, such a disk is considered as a raw. Block Size When formatting a Datastore, we have to define block sizes. A block is the minimum size that a file occupies and this is defined while creating a file system. For example for a block size of 8Kb, a file of 1kb will occupy 8kb. Similarly a file of 18 Kb will occupy 3 blocks (24Kb). Its important to note that a block can only be occupied by a single file, meaning if a file occupies half the size of block, it will not share that remaining free space on the block with another file. Now if I format the file system with 8Mb block size I get 2Tb of disk space. This space will be used for creating virtual machines.
  9. 9. What is a Datastore? A datastore is a logical storage unit that can use disk space on one physical device or one disk partition, or span several physical devices. Types of datastores: 1.VMFS 2.Network File System (NFS) Datastores are used to hold virtual machines, templates, and ISO images. A VMFS datastore can also hold a raw device mapping (RDM), which is used to access raw data. VMFS Datastore: It can recognize only upto 2 TB LUN A VMFS datastore can extend spanning multiple LUN’s with a maximum of 32 LUNs, meaning a single datastore can be of 64 TB. (This is not a good practice though) Allows concurrent access to shared storage Can be dynamically expanded Can use an 8MB block size, good for storing large virtual disk files Provides on-disk, block-level locking You can format local disk, SAN or iSCSI to create a datastore
  10. 10. VMFS can be formatted with different block sizes which are defined while creating datastores. For example a 2 TB Disk Formatted with 1MB block size, maximum file size will be 256 GB 2MB block size, maximum file size will be 512 GB 4MB block size, maximum file size will be 1 TB 8MB block size, maximum file size will be 2 TB Minimum size that a small file example of 1 KB will occupy a single block with a block size for example 1MB, even if data in the file is 1KB. You cannot store more than a single file in a block. Block size and vmdk size limitation Note: When you create a VMFS datastore on your VMware ESX servers many administrators select the default 1MB block size without knowing when or why to change it. The block size determines the minimum amount of disk space that any file will take up on VMFS datastores. So an 18KB log file will actually take up 1MB of disk space (1 block) and a 1.3MB file will take up 2MB of disk space (2 blocks). But the block size also determines the maximum size that any file can be, if you select a 1MB block size on your data store the maximum file size is limited to 256GB. So when you create a VM you cannot assign it a single virtual disk greater then 256GB.
  11. 11. There is also no way to change the block size after you set it without deleting the datastore and re-creating it, which will wipe out any data on the datastore. Because of this you should choose your block size carefully when creating VMFS datastores. The VMFS datastores mainly contain larger virtual disk files so increasing the block size will not use all that much more disk space over the default 1MB size. Block size and performance Besides having smaller files use slightly more disk space on your datastore there are no other downsides to using larger block sizes. There is no noticeable I/O performance difference by using a larger block size. When you create your datastore, make sure you choose your block size carefully. 1MB should be fine if you have a smaller datastore (less than 500GB) and never plan on using virtual disks greater then 256GB. If you have a medium (500GB – 1TB) datastore and there is a chance that you may need a VM with a larger disk then go with a 2MB or 4MB block size. For larger datastores (1TB – 2TB) go with a 4MB or 8MB block size. In most cases you will not be creating virtual disks equal to the maximum size of your datastore (2TB) so you will usually not need a 8MB block size
  12. 12. RDM or Raw Device Mappings is a method of presenting a RAW LUN to a Virtual Machine RDM’s provide a way for Virtual Machines to Access disks directly bypassing the Virtualization Layer RDM’s are used for Cluster applications like MCS (Microsoft Cluster Services) when creating a cluster between a Physical and a Virtual Machine RDM Mapping are supported for the following devices SCSI SATA Fibre Channel iSCSI RDM
  13. 13. What Files Make Up a Virtual Machine?
  14. 14. VM Files VMX file – The size of these files will be in KB’s Log files, cannot grow more than MB’s vmxd file, snapshot description file, NVRAM file, vmdk and flat.vmdk What are the difference between vmdk and flat.vmdk Vmdk is the description of the Virtual Disk and flat.vmdk is the actual disk for that particular virtual machine. So it is a file which is acting as a disk for a virtual machine. So when we create or provide a virtual disk for a virtual machine it has to be kept on VMFS volume/datastore. So coming to conclusion it means when we format a VMFS volume with 1 MB block size, we can create a maximum virtual disk for a virtual machine of 256 Gb, and so on.
  15. 15. SAN (Storage Area Network) SAN Disks Storage Processor (HBA) HBA ESX / ESXi 0 1 ESX / ESXi 0 1 FC Switch Interconnecting Multiple nodes using a FC Switch is called a Fabric
  16. 16. SAN (Storage Area Network) Depending on the appropriate needs the SAN Administrator will create a Hardware RAID and then create a LUN LUNs are identified by their id, example 0, 1, 2 etc LUN ids can be dynamically generated or can be created static From the ESX Server side the HBA’s are recognized using WWN (World Wide Node name), similar to the MAC Address of the ethernet controller WWN is a 64 bit hexadecimal value assigned to the HBA by the vendor ESX admin needs to provide the WWN to the Storage Administrator ESX Servers can recognize upto 8 HBA and upto 16 paths per LUN But ESX Supports a maximum of 1024 paths from all the ESX Servers
  17. 17. SAN (Storage Area Network) SAN Disks Storage Processor (HBA) HBA ESX / ESXi 0 1 ESX / ESXi 0 1 FC Switch Storage Group WWN1, WWN2 WWN3, WWN4 WWN1 WWN2 WWN3 WWN3 Since WWN’s are 64 bit hexadecimal numbers and its difficult to remember, the Storage Admin creates a Alias to the WWN's giving them a friendly name, example for ESX1 he chooses ESX1 as the name and ESX2 respectively
  18. 18. LUN Mapping & LUN Masking is done at the Storage End SAN Disks Storage Processor (HBA) HBA ESX / ESXi 0 1 ESX / ESXi 0 1 FC Switch Storage Group WWN1, WWN2 WWN3, WWN4 WWN1 WWN2 WWN3 WWN3 Depending on the Storage make a single LUN can be presented to 128 Nodes
  19. 19. Identifying HBA’s HBA are identied by vmhba, vmhba1 and so on. Each and every HBA has a controller which is always 0 Disks Storage Processor (HBA) HBA ESX / ESXi 0 1 FC Switch Storage Group LUN1 vmhba0 Controller 0 Vmhba1 controller 0 T1 T2 When you can access a LUN using multiple path it provides multipathing. Multipathing provides continuous access to a LUN incase of a hardware failure
  20. 20. Multipathing Policies ESX / ESXi supports multipathing policies NMT – Native Multipathing Polices which consists of Fixed – Provides only Fault Tolerance Most Recently Used (MRU) – Provides only Fault Tolerance Round Robin – Provides both Fault Tolerance as well as Load balancing When using fault tolerance using Fixed and MRU, one becomes a active path and the other becomes as passive path and is used only incase of a failure of the HBA currently being used, switching it to the 2nd HBA In Fixed multipathing when a failed HBA recovers from a failure it becomes active changing the state of the secondary HBA from active to Passive But incase of MRU when a failed HBA recovers it goes into a passive mode since the last used path was of the secondary HBA In round robin both HBA’s are in active active mode Storage vendors might have their own multipathing policies which might not be recognized by ESX Server, so kindly check with the vendor before buying the storage. Storage vendors might provide multipathing as a plugin to be installed
  21. 21. Fibre Switch Disks Storage Processor (HBA) HBA ESX / ESXi 0 1 FC Switch Storage Group LUN1 T1 T2 For security a storage admin can configure zones at the FC Switch. Zones are 2 types Soft Zone Hard Zone
  22. 22. Zoning Hard Zone Is configured for the ports of the FC Switch If a cable is plugged out from the zone port and attaches to another port outside the zone, the LUNs are lost. Port need to be reconfigured in the hard zone in this case But if the HBA is changed and reconfigured with its WWN on the storage, no changes are needed to be done on the FC Switch Soft Zones Are configured using WWN’s Changing ports does not affect access to LUNs If a HBA is changed the soft zones need to be reconfigured
  23. 23. What is the difference between a Fibre Channel and a iSCSI?. Both are SAN • iSCSI uses IP based connection • Fibre Channel uses Fibre HBA For a Fibre channel, the Fibre Channel storage is connected to a FC Switch which is connected to a FC HBA on the ESX host. For a iSCSI, iSCSI storage is connected to a Ethernet network or you can use a hardware initiator. What is a initiator?. An initiator is similar to a HBA. You have a hardware initiator, similar to a Fibre channel HBA. FC HBA will have a Fibre channel port, iSCSI initiator will have a Ethernet Port. A hardware initiator has a controller. The role of a controller is to encapsulate SCSI protocol into IP protocol for transportation from one end to the other end it has to use the IP. Or i can use a plain NIC also which can also communicate using Ethernet technology. In this case the NIC does not have the capability of encapsulating SCSI protocol into IP protocol. In this case you have to use software initiator. Software initiator uses CPU cycles since the NIC does not have a controller like a hardware initiator.
  24. 24. Understanding iSCSI Storage iSCSI (Internet SCSI) is sending SCSI disk commands and data over a TCP/IP network Why use it? 1.Low cost 2.Use existing hardware - Ethernet NIC, switch, and OS features 3.Supports almost all vSphere features
  25. 25. Understanding iSCSI Storage Downside – performance? and reliability? iSCSI Terms: • iSCSI hardware initiator - a special iSCSI NIC card • iSCSI software initiator - use your own NIC card and OS iSCSI software • iSCSI Target - the server running iSCSI
  26. 26. Disk Arrays SP Ethernet Switch TCP/IP Network ESX/ESXi NIC This can be a NIC or iSCSI HBA iSCSI uses TCP/IP Protocol and uses IQN (iSCSI Qualified Name) naming convention
  27. 27. Understanding iSCSI Storage iSCSI uses IQN (iSCSI qualified name) to identify iSCSI Targets & Initiators It is laid out in this format: • date in year-month format • reversed domain of the iSCSI hardware provider, example qlogic, if it’s a software iSCSI then for example Microsoft might have provided the iSCSI software. • a unique organization assigned name (ie: hostname) • For example: 2009-10.com.hpesindia:iscsi1
  28. 28. Understanding iSCSI Storage Configuring iSCSI Hardware Initiator (HBA) Login to the iSCSI storage and reboot Go to the bios of the System and then to the BIOS of the HBA to configure the IP Software Initiator (Only for ESX Server) By default the daemon iscsid is disabled The iSCSI port 3260 is blocked by the firewall iSCSI uses VMkernel connection type and ESX by default does not have a VMkernel type On ESXi everything is configured by default, all an admin has to do is enable the software iSCSI initiator
  29. 29. Understanding iSCSI Storage Configuring iSCSI iSCSI uses 2 types of discovery method to connect to a iSCSI storage Static – Manually enter IP Address and the IQN informing the ESX to connect to the iSCSI Storage Send Target (Dynamic)
  30. 30. Send Target (Dynamic) Disk Arrays SP Ethernet Switch TCP/IP Network ESX/ESXi NIC Win2k For Dynamic Discovery you need an additional system with a special software like iNS (iSCSI Name Server Software). iNS will resolve IQN’s just like a DNS Server resolves Host Names to IP Address. It contains database of all IQN and at the ESX Server end an admin needs to put the IP Address of the iNS Server
  31. 31. Send Target (Dynamic) Lun Mapping and LUN Masking can be done at the iSCSI Storage System These are done in 2 ways On IP Address Or IQN
  32. 32. NFS NFS is supported by ESX/ESXi CIFS is not supported at all By default 8 NFS volumes can be mounted This figure can be changed and upto 64 NFS volumes can be mounted on a single ESX box In this way, ESX supports 256 LUNs or Disks and 64 NFS which makes a total of 320 Datastores
  33. 33. NFS NIC Ethernet Switch TCP/IP Network ESX/ESXi NIC NFS is a file level access Configured in /etc/exports And then execute the command exportfs On the ESX/ESXi side the admin should know the IP Address of the NFS Server and the mount point NFS also uses VMkernel. Unix/Linux Disks /data (rw, norootsquash) /mnt/nfs

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