What version of z/OS?
I do not think zFS can do anything other than 8k blocks zFS always reads and writes data in 8K blocks. However, in z/OS® V1R13, zFS stores data either inline or in 8K blocks. (Inline data is a file that is smaller than 53 bytes and is stored in the file's metadata.) Unlike in previous releases, zFS R13 no longer stores data in 1K fragments. zFS R13 can read data stored in fragments; however, when the data is updated, it is moved into 8K blocks. Previously, zFS could store data in 1K fragments (contained in an 8K block). This meant that multiple small files could be stored in a single 8K block. I think a zFS can be an EA/EF Vsam linear dataset that would allow it to grow over the 4GB limit. Lizette > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:[email protected]] On > Behalf Of John Compton > Sent: Wednesday, October 29, 2014 2:41 AM > To: [email protected] > Subject: ZFS dataset space allocation query > > I've recently been having a bit of fun(?) solving a problem where one of our > ZFS > clusters was allowed to fill all the space allocated to it. > > Along the way I (re)discovered in "Distributed File Service zSeries File > System > Administration" (SC24-5989): > > <quote> > ...Assuming that each volume is a 3390 with 3338 cylinders (with 3336 > cylinders > free), that there are 15 tracks per cylinder and that you can get > 6 8K blocks per track (15 x 6 = 90 8K blocks per cylinder), you should get > 90 x 3336 = 300240 8K blocks per volume and 10 x 300240 = 3002400 8K blocks in > the aggregate... > </quote> > > > My question is: "Is there any way to change that 8K block size up to something > larger?" > > When defining the linear cluster in the first place, can I, for instance, > specify a > CISIZE of, say, 27648 bytes - without being overridden by some in-built > limitation? > > > The reason I ask is that with 8K blocks, you - as the manual states - get 6 > blocks per > track. With a track size of 56664 bytes, this means that you use > 49152 bytes on each track. In other words, 13% of the allocated disk space is > quite > simply being thrown away. > Yes, yes, yes - I _know_ that "disk space is cheap" these days but 13% waste > still > strikes me as a bit much to have to swallow. If I could bring it down to less > than 5% > or so, I'd feel a lot happier. > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
