EMC Storage Product Knowledge Sharing

Lets first disuss what is Powerpath software. If you are familiar with EMC product and then definitelly will be using EMC Powerpath software. Those who are new to storage world, it will interesting to know about this product as there are only few software in this category like DMP,PVLINK, LVM etc from other vendor. This sofware is one of the most robust compare to other, thats reason EMC generationg more revenue out of this Product.......

What are the differences between failover modes on a CLARiiON array?A CLARiiON array is an Active/Passive device and uses a LUN ownership model. In other words, when a LUN is bound it has a default owner, either SP-A or SP-B. I/O requests traveling to a port SP-A can only reach LUNs owned by SP-A and I/O requests traveling to a port on SP-B can only reach LUNs owned SP-B. It is necessary to have different failover methods because in certain situations a host will need to access a LUN on the non-owning SP.The following failover...

DMP With CLARiiON:-CLARiiON arrays are active-passive devices that allow only one path at a time to be used for I/O. The path that is used for I/O is called the active or primary path. An alternate path (or secondary path) is configured for use in the event that the primary path fails. If the primary path to the array is lost, DMP automatically routes I/O over the secondary path or other available primary paths.For active/passive disk arrays, VxVM uses the available primary path as long as it is accessible. DMP shifts I/O to...

SUN/SOLARIS___________To display what HBA's are installed.#prtdiag -v#dmesg#cat /var/adm/messages grep -i wwn moreTo set the configuration you must carry out the following:-changes to the /etc/system file-HBA driver modifications-Persistent binding (HBA and SD driver config file)-EMC recommended changes-Install the Sun StorEdge SAN Foundation packageChanges to /etc/system: ( Plz ignore 3 equal sign when u edit the file)SCSI throttle === set sd:sd_max_throttle=20Enable wide SCSI === set scsi_options=0x7F8SCSI I/O timeout value...

Handling BCV and Clone Disk on Veritas Volume Manager. Get Output of Vxdisk List command# vxdisk listVxdisk list command showing that some disks are marked with the udid_mismatch flag.Write a New UUID to DiskYou can use the following command to update the unique disk identifier (UDID) for one or more disks:# vxdisk [-f] [-g diskgroup] updateudid disk ...Note : The -f option must be specified if VxVM has not raised the udid_mismatch flag for a disk.Importing a disk group containing cloned/BCV disksYou can then import the cloned...

I tried to collect some good information on iSCSI driver details which was request by some reader. Hope this will help you on iSCSI queries. Leave comment if it is useful... I will try to write iSCSI overview in next entry. Happy Reading!!!!!!The iSCSI driver provides a transport for SCSI requests and responses to storage devices via an IP network instead of using a direct attached SCSI bus channel or an FC connection. The SN 5400 Series Storage Router, in turn, transports these SCSI requests and responses received via the IP...

Mount EMC BCVs at the same hostExample:I have created a volumegroup, a logical volume, afilesystem and a file on two EMC standard volumes.(For this test you need to have two hdisks hdisk and hdisk andtwo BCVs dev and available)# mkvg -f -y MyName_vg -s 16 hdisk hdisk# mklv -y MyName_lv -b n MyName_vg 20# crfs -v jfs -d MyName_lv -m /MyName_mp -A yes -p rw# mount /MyName_mp# lptest > /MyName_mp/lptest.outFor using EMCs TimeFinder I have to create a device group.(AIX is working with volumegroups. EMCs TimeFinder is working...