EMC Symmetrix DMX-3 brings one of the most powerful networked storage solution available. It builds on the proven success of the Symmetrix Direct Matrix Architecture—while bringingthe new levels of capacity and performance. So it benefits from a powerful combination of incremental scalability, constant availability, and exceptional data mobility.
Symmetrix DMX-3 enables massive consolidation to deliver all the benefits of tiered storage in one system. And it offers the flexibility to address the changing needs of business—quickly and effectively. For the most extreme, demanding storage environments, Symmetrix DMX-3 provides a powerful solution that’s also remarkably simple to manage.
The DMX-3 consists of a single system bay and from one to eight storage bays. The system bay contains the 24-slot card cage, service processor, power modules, and battery backup unit (BBU) assemblies. The storage bays contain disk drives and associated BBU modules. In a highly scalable component and cabinet configuration,the DMX-3 has the capacity, connectivity, and throughput to handle a wide range of high-end storage application.
Its an Active-active storage system .In an active-active storage system, if there are multiple interfaces to a logical device, they all provide equal access to the logical device. Active-active means that all interfaces to a device are active simultaneously.
DMX-3 system applies a high degree of virtualization between what host sees and the actual disk drives. This device has logical volume address that the host can address.A symmetric Device is not a physical disk.Before actually hosts see the symmetric device, it needs to define path, means mapping the devices to Front-end director and then it needs to set FA-PORT attribute for specific Host.Symmetric device is not a physical disk.
We can create up to four mirrors for each Symmetric device. The Mirror positions are designed M1, M2, M3 and M4. When we create a device and specify its configuration type, the Symmetrix system maps the device to one or more complete disks or part of disks known as Hyper Volumes/Hypers. As a rule, a device maps to at least two mirror means hypers on two different disks, to maintain multiple copies of data.
HP-UX: With HP-UX DMX supports the PV link, Native 11.31 multipath & powerpath. Unlike CX we can use any of the path as 1st device in volume group as all paths are active. But it should be kept in mind that the load should be distributed between the HBAs. So check the complete HW path and then extend the volume group.
Set the below flag for HP-UX 11.11 & 11.23 on FA port
#set port 7a:0 Volume_Set_Addressing=enable;
#set port 8a:0 Volume_Set_Addressing=enable;
Set the below flag for HP-UX 11.31 on FA port
#set port 7a:1 Volume_Set_Addressing=enable, SPC2_Protocol_Version=enable, SCSI_Support1=enable;
#set port 9a:1 Volume_Set_Addressing=enable, SPC2_Protocol_Version=enable, SCSI_Support1=enable;
As given above earlier port usage were based on the specific flavor of UNIX and in particular for HP-UX. We can also do the same but based on host port WWN and not on FA port basis. This enables us to map different host platforms to the same storage ports. Flagging per HBA WWN does not solve all problems with HP-UX. This platform still does not understand LUN IDs greater than 7. When mapping LUNs for HP-UX to storage ports that are already in use by any other platforms in most cases we get LUN IDs that are greater than 7. If we use ordinary mapping/masking scripts, those LUNs will be invisible by HP-UX.
A solution is to use ‘-dynamic_lun’ option in masking script. It assigns host LUN ID according to HBA and not according Storage Port LUN ID:
#cat mask.hpux1
symmask -sid 888 -wwn 50060b0000306d6e add devs 021F -dynamic_lun -dir 7B -p 1 -nopropmt
symmask -sid 888 -wwn 50060b0000306de2 add devs 021F -dynamic_lun -dir 9B -p 1 -nopropmt
symmask refresh -nop
symcfg discover
Generally we can assign specific host LUN IDs with –lun option but in most cases it is not required.
When connecting a new HP-UX 11.31 host we need to set the below port flag which will help us in using the agile devices.
symmask -wwn 500110a00085bcf6 set hba_flags on SC3,SPC2,OS2007 -enable -dir 8a -p 0
symmask -wwn 500110a00085bcf4 set hba_flags on SC3,SPC2,OS2007 -enable -dir 10a -p 0
symmask refresh -nop
symcfg discover
Verify the above by using
#symmaskdb list db -dir 8a -p 0 -v
It should show as below for the specific WWN
Port Flag Overrides : Yes
Enabled : SPC2_Protocol_Version(SPC2)
SCSI_Support1(OS2007)
To mask a new device to a host we need to 1st check the free devices on the DMX. Below command is used to see the free devices
#symdev list -noport
Make a note of the required Sym device and also check the Config to whether it's 2-Way Mir or
RAID-5 device. For this we need to find on which FA port the host is zoned. Below command will tell us on which FA port the host is zoned.
#symmask list hba
#symmaskdb list devs -wwn 500110a00085bcf4
Once the FA ports are found then we need to map the device to it. Below commands illustrates both meta creation and mapping.
#vi meta.server
form meta from dev 052A, config=striped, stripe_size=2cyl;
add dev 052B to meta 052A;
form meta from dev 052C, config=striped, stripe_size=2cyl;
add dev 052D to meta 052C;
And then execute it using
#symconfigure -sid 888 -f meta.server preview
#ymconfigure -sid 888 -f meta.server prepare
ymconfigure -sid 888 -f meta.server commit
Once done then find out the free using below command
#symcfg list -dir 8a -p 0 -addr -avail
Make a note of vbus, TID and LUN and the free address are marked as *. Create the map file as below. You can also use : and keyword starting target when you want to use range of Sym devices
#vi map.server
map dev 05AA to dir 9D:0, target=0, lun=02C;
map dev 05AA to dir 7D:0, target=0, lun=02B;
map dev 05AC:05AE to dir 9D:0 starting target=0, lun=035;
map dev 05AC:05AE to dir 7D:0 starting target=0, lun=035;
Save the file and run the commit the mapping using below command
#symconfigure -sid 888 -f map.server preview
#symconfigure -sid 888 -f map.server prepare
#symconfigure -sid 888 -f map.server commit
If there is any problem in the map file then during preview itself it will throw the errors.
Once mapping is done then just mask the devices to the specific host WWN
#vi mask.server
symmask -sid 888 -wwn 2100001b321a8fef add devs 02AD,0582 -dir 7D -p 0 -nopropmt
symmask -sid 888 -wwn 2101001b323a8fef add devs 02AD,0582 -dir 9D -p 0 -nopropmt
symmask refresh -nop
symcfg discover
Just execute the command using
#sh -x mask.server
You can also check the masking again by using the below command. It will show on which FA port and WWNs the Sym device is mapped and masked.
#symmaskdb list assignments -dev 01CE
To delete a device from host side, make a note of the Sym device from the below command
#sympd list
The above command shows both physical path of the disk and the corresponding Sym device ID.
Make sure that the device is mapped & masked to the specific FA and host WWN respectively using the above symmaskdb command. There may a situation where the device is mapped and masked to multiple host of a cluster and decommissioning a node of a cluster doesn't mean deleting the LUN.
Create unmask file as below
#vi unmask.server
symmask -sid 888 -wwn 2100001b321a39ef -dir 7D -p 0 remove devs 059C,059D,05A5,05A0,059F,05A4
symmask -sid 888 -wwn 2101001b323a39ef -dir 9D -p 0 remove devs 059C,059D,05A5,05A0,059F,05A4
symmask refresh -nop
symcfg discover
Execute it using
#sh -x unmask.server
Once it's unmasked do a write disable of the device (Note: If the device is used in a cluster then just exit after unmask)
#vi write_disable.server
symdev -sid 888 -nop write_disable 052A
symdev -sid 888 -nop write_disable 052B
Execute it using
#sh -x write_disable.server
Once done and go ahead with unmap
#vi unmap.server
unmap dev 052A from dir 9D:0;
unmap dev 052A from dir 7D:0;
Execute is using
#symconfigure -sid 888 -f unmap.server preview
#symconfigure -sid 888 -f unmap.server prepare
#symconfigure -sid 888 -f unmap.server commit
Now the below command will show if the device is free or not
#symdev list -noport
A ???:? can be see in the device if its free. (* represent that the device is being mapped to FA port)
If the device that we unmapped is a meta then we can also dissolve it using below command
#vi dissolve.server
dissolve meta dev 052A
Execute it using
#symconfigure -sid 888 -f dissolve.server preview
#symconfigure -sid 888 -f dissolve.server prepare
#symconfigure -sid 888 -f dissolve.server commit
Solaris: With Solaris it supports Veritas DMP & Powerpath. Check the Symmetrix specific ASL with Veritas.
LINUX: With LINUX we can use powerpath or the inbuilt device mapper.
#vi port.server
symmask -wwn 2101001b32a8c3d5 set hba_flags on D -enable -dir 7b -p 1
symmask -wwn 2100001b3288c3d5 set hba_flags on D -enable -dir 9b -p 1
symmask refresh -nop
symcfg discover
Execute it using
#sh -x vi port.server