Storage Array components explained in a Video EMC CLARiiON CX310 iSCSI
Posted on 20. Jul, 2008 by admin in SAN, Storage area network, Uncategorized, emc, interview questions
SAN hardware overview – EMC CLARiiON CX310 iSCSI
Storage Area Network Hardware components explained using a product from EMC with the model name CLARiiON CX310 based on iSCSI protocol
Since a SAN or any Enterprise Storage solutions is quite expensive not everyone of you might have seen or worked on a SAN box(SAN storage array). This video shows CLARiiON model of EMC’s Storage array.Usually if you are beginner in storage industry you wont be allowed to directly access or configure a storage array hence this Video can definitely be helpful.
A SAN consists of a Storage Array which is shown in this Video. It consists of several Disk trays holding nearly 14 or 16 Hard Disk Drives(HDDs) each.The whole storage array may consist somewhere around 1 to 8+ disk trays or more based on the expense/budget of the buyer. So if you have 4 disk trays each holding 15 hard drives you have 4X14=60 Hard drives.If each of these hard drive has a capacity of storing 500GB data then you have a total capacity of 30,000GB or 30Terra Byte(30 TB). That much storage is not always used by 1 or 2 hosts(server).A production environment implementation of a SAN solution will have more than 10 to 100s of servers sharing such a Storage capacity.
Also since SAN equipment is very expensive it makes business sense to share this storage across multiple hosts(servers).
SAN can be of 2 types :
1.FC (Fibre Channel) based SAN
2.iSCSI (SCSI over IP) based SAN
These are the connectivity mode between a Storage array & the Servers. FC SANs were very common earlier & were very very expensive. Now we will see more & more of iSCSI based SAN & they are quite inexpensive compared to FC SANs. In future most of the SAN storage arrays released by major Storage companies like EMC,NetApp,HP,Dell,IBM will support both FC as well as iSCSI. Few clients(Who wanna buy cheaper storage solutions for their business) may just go for only iSCSI based SANs & may never plan to implement FC based environment. For them the storage companies may just build storage arrays which support only iSCSI.
In the video: This is a EMC CLARiiON CX310 iSCSI with 60 Hard drives.Around 18TB of storage capacity ignoring RAID 10 & RAID5 configurations which reduces the available capacity. We have other videos covering RAID,FC,iSCSI in detail.
At the top row of the Storage array are 750GB storage capacity SATA(Serial ATA) HDDs(Hard disk drives) each running at 72000 rpm(Revolutions per minute) (72K rpm).These are inexpensive compared to SAS(Serial Attached SCSI). SATA drives are not very great in speed & performance compared to SAS or FC based HDDs. Hence SATA are primarily used for long time archival or backup puproses.
Rest of the 3 disk trays or Disk expanision units are each having 15 HDDs, each 300GB storage capacity HDDs running at 10K rpm.All of the drives(HDDs) on this storage array are hot swappable or hot pluggable – meaning you can take the HDDs out & replace with a new one while the storage array is powered & running. You dont need to bring down the whole storage array just to replace 1 or more faulty drives.In a production environment a SAN storage array is not supposed to have any downtime hence this hot plug/hot swap feature is a MUST in most of the storage products.
At the bottom of the Storage array is the Power Backup for this whole storage array(UPS Batteries).
In the video there is one rack holding our Storage array & next rach has series of servers(hosts or initiators) which are sharing our single storage array of nearly 18TB capacity.This SAN box holds nearly 400 Databases in it.
In the video we see the back side view of the storage array to find Storage controllers(Also called Storage processors – SP) each having 1 Gigabit iSCSI connectivity. There are cascade cables which go to the rest of the Disk trays(Disk Expansion Units).
If we had a FC based SAN connectivity we could have got 2Gigabit(2Gb) or 4Gb connectivity but that would have been very expensive compared to iSCSI based which gives only 1 Gb. Each disk tray or disk bay has redundant power supply ( 2power supply units- if 1 fails onther still keeps the unit Up).The UPS batteries at the bottom of storage also has redundancy or fault tolerance in case the main Power supply coming into the storage array fails. Rack which holds this whole storage array has Power Distribution Unit(PDU) which are switches having power outlets to connect multiple drive bays.
Later video covers how to configure an iSCSI SAN storage array – how to allocate drive space, how to map hosts to these drives(luns).
2 Comments
Ramakrishna
08. Sep, 2008
The content is really helpful to the people who dont have acces to real environment.I appreciate your afford in educating such people.
ok
24. Sep, 2008
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