Where did my space go?

So here is how that report get its numbers. The unused RAID group capacity is the sum of all free space in all RAID groups. It then breaks that number down in by RAID type. So by the output you listed you have 1030GB of free space combined from all of your RAID5 groups. The unused physical disk capacity is simply the sum of all unbound disks in each enclosure. From the output you listed, you have 1073GB of unused disks in bus 3 encl 1.

It looks like you used all the unused disks in bus 3 encl 1 to create a RAID5 group but did not use all the space in that RAID group to create your new LUN. So logically the sum of all free space in all RAID groups will be larger now since you added a RAID5 group and did not allocate all the space from that RAID group. And the unused physical disk capacity will be zero since you used the last remaining unbound physical disks to form the new RAID group.

I forgot to mention, there is another report that will help you find the free space in each RAID group. Run the RAID Groups report for your array, it will list the RAID group, the total space and the free and contiguous free space in the RAID group.

Also, the Available Storage report that you ran will present a graphical view of each enclosure on the array with the RAID groups and unused disks listed within each enclosure. This is an easy to interpret graphical view of your disk configuration.

Play around with some of the other reports as well, there is lots of good info to be had in the reports.

One small possibility:  if you have created/deleted LUNs on various RAID groups, the space left by the deletion fragments the free space in the RAID group.  If there are large number of gaps, the largest contiguous space for a new LUN grows smaller.

Karl

Thanks.  the raid groups report clears it up for me.

would you know what is using the space between the raw and usable space?

Sorry for the questions, but running the Raid Groups Report, i notice that i have

Raid      Type     Total     Free     Contiguous     LUNs

grp ID               Space   Space    Free    

     9      raid5      0          805       805                blank

why is there a 0 in the "total space" does that mean total space allocated?

when i go to the raid group in the manager and select bind lun, i see that i can assign 805.  is my interpretation correct?

Thanks.

The Total Space column should display the size of the RAID group, it should not display 0. Not sure why your report is listing 0 for the Total Space. The free and contiguous space lists what is usable in the RAID group. As Karl pointed out if you have multiple LUNs in the RAID group with gaps between them then your contigous space will be less than the free space and you would need to defragment the RAID group so that the full space is available.

You also asked about raw versus usable space. These can be misleading terms. The raw space is simply the sum of all the unused disks in the array. So if you have five 146GB drives (133.6GB raw) then your raw space is 5 x 133.6 = 668GB. But if you bind those five drives into a RAID5 group you lose one disks worth of capacity to RAID overhead so your usable space for that RAID group is 534GB. The unused space from the Storage Report is the sum of all free space across all RAID groups in the array.

Thanks for the good response.  (the light bulb is going on for me - it is just the energy efficient one so it takes time )

Do you know what the correct terminology is for

the 146GB drive (is that called the drive size)

the 133.6GB = Raw usable capacity (before a raid is created)

the "534" in your example = "Raid usable capacity"

If your boss wanted an executive summary of the space, what would you provide to him:

The "Available Storage Report" and the "Raid Group Report"?

To get an accurate view (exec summary) of the storage, would it be correct to say that you need only the "Available Storage Report" where the total of the "Unused Raid Capacity" and total of the "Unused Physical Disk capacity" gives you all the usable space (with the understanding that space will be lost when the physical disk capacity is created into a RAID)

Thanks a million for the clear responses (karl too).  It is truly appreciated.

I think I am good now.  i will have to research the Free space of 0 in my raid report.

Thanks.

Furthermore: on a Clariion a sector is 520 bytes instead of 512 and the common mistake people make is that they think 1TB equals 1024 x 1024 x 1024 x 1024, while in fact Giga means 1000, so 1 TB = 1,000,000,000,000 bytes. So a 1TB disk equals about 930GiB (binary Gigabyte). You never lost any space anywhere except the already explained hot spare and raid group overhead.