This infodoc gives a preview of the terminology and procedures associated with the Sun StorEdge [TM] 9910 and Sun StorEdge [TM] 9960 disk arrays. The StorEdge 9960 consists of one DKC (disk control frame) and at least one DKU (disk unit). However the SE9960 can consist of up to 6 DKU's; 3 to the left of the DKC and 3 to the right of the DKC. In the SE9960 a DKU contains 8 HDUs (hard disk unit). The StorEdge 9910 is one physical cabinet with 4 HDU's in the back. One HDU can contain up to 12 HDD's (hard disk drives). A B4 is made up of 4 HDUs , which means that a DKU in an SE9960 has two B4s and an SE9910 contains one B4. A parity group consists of exactly 4 HDDs, in the same slot numbers, spread across each HDU in the same B4. So and HDU can be a part of 11 parity groups if there is a spare disk in the HDU, or 12 parity groups if there is no spare disk.

To configure the new parity group, we must:

1. Choose a Raid Level

2. Select the Drive Size

3. Select the Emulation [different emulations give different size LDEVs (logical device) and are good for certain specific OS on the host]

4. Assign a CU (control unit) and starting LDEV ID [ Note: There can be total of 16 CUs in a StorEdge99x0, 256 maximum LDEVs per CU, therefore up to 4096 total LDEVs ]

5. Map a LUN [This LUN would be the one that you would see as the drive on your host]

Remember: You can not mix different size drives and different raid levels within the same parity group.

Now that we know that how we can create a LUN from an LDEV, we would like to attach multiple LDEVs to create a bigger LUN. We can do this with what we call LUSE, or Logical Unit Size Expansion.

The following are the LUSE guidelines:

• All LDEVs must be from the same CU.
• LDEVs can not be 'mapped'.
• Maximum number of LDEVs that you can LUSE together is 36.
• You can combine CVS (will be explained later in this infodoc) volumes into LUSE but the condition is that the CVS volumes should be of the same size, same emulation type and from the same CU.
• You can not do CVS operation on LUSE volumes.
• You can not combine a CVS volume and a normal volume into a LUSE volume.
• You can not add Raid-1 and Raid-5 into a LUSE volume.
• You can not combine different emulation types (open-3, open-k, ...) into same LUSE volume.

Another tool like LUSE is CVS, or Custom Volume Size. CVS may also be seen with the name VLVI (virtual logical volume image) or Virtual LUN.

When we assign an emulation type to a parity group we have no control over the size of an LDEV, so usually we are left with some unused disk space in our parity group. CVS process is used to claim unused space mentioned above. CVS creates smaller LDEV to be used in DCR (dedicated cache residency). DCR is a permanently configured part of cache during installation which is dedicated to an assigned LDEV. Remember: cache keeps the data in read/write process while shared memory keeps the info about where the data is in cache. The amount of storage determines the cache you need and the cache you need determines the shared memory you would need. On the same lines, the number of CUs you have determines the cache/shared memory you need.

The following are some CVS guidelines:

• LDEVs for conversion to CVS volumes must be in the same parity group.
• All emulation type open vols must be offline/unmounted from the host, i.e. not "mapped".
• LUSE vols are not supported for CVS operation.
• Minimum size of a CVS vol is 35MB.
• open-L and open-M volumes are not supported for CVS operation.

Now that we have desired amount of LUNs we want, how about backups. Shadowimage is for within the system copies and TrueCopy is for across systems copy. Shadowimage may also be seen with the name HMRCF. Truecopy may be seen with the name HRC.

The following are some shadowimage guidelines:

• Its a continuous operation used for point-in-time and disaster recovery procedures.
• CVS and LUSE vols are supported.
• P-vols and S-vols (primary and secondary volumes are designated for the copy process) must be of the same emulation type.
• CVS and LUSE P-vols must be paired with the S-vols of the same type and capacity.
• All combinations of RAID levels are supported.

• Susheel.Chawla@East.Sun.COM
• http://Storage.East