Re: [zfs-discuss] zfs send & tape autoloaders?

heheheh, ok, I'll stop after this. ;-) Sorry for going on so long, but it was fun. In 2007, IDC estimated the size of the digital universe in 2010 would be 1 zettabyte. (10^21 bytes) This would be 2.5*10^18 blocks of 4000 bytes. http://www.emc.com/collateral/analyst-reports/expanding-digital-

Re: [zfs-discuss] zfs send & tape autoloaders?

On 01/12/11 04:15 AM, David Strom wrote: I've used several tape autoloaders during my professional life. I recall that we can use ufsdump or tar or dd with at least some autoloaders where the autoloader can be set to automatically eject a tape when it's full & load the next one. Has always w

Re: [zfs-discuss] zfs send & tape autoloaders?

> From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss- > boun...@opensolaris.org] On Behalf Of David Strom > > So, has anyone had any experience with piping a zfs send through dd (so > as to set the output blocksize for the tape drive) to a tape autoloader > in "autoload" mode? Yes. I'

Re: [zfs-discuss] (Fletcher+Verification) versus (Sha256+No Verification)

In case you were wondering "how big is n before the probability of collision becomes remotely possible, slightly possible, or even likely?" Given a fixed probability of collision p, the formula to calculate n is: n = 0.5 + sqrt( ( 0.25 + 2*l(1-p)/l((d-1)/d) ) ) (That's just the same equation

Re: [zfs-discuss] (Fletcher+Verification) versus (Sha256+No Verification)

For anyone who still cares: I'm calculating the odds of a sha256 collision in an extremely large zpool, containing 2^35 blocks of data, and no repetitions. The formula on wikipedia for the birthday problem is: p(n;d) ~= 1-( (d-1)/d )^( 0.5*n*(n-1) ) In this case, n=2^35 d=2^256 The problem is,

Re: [zfs-discuss] Mirroring raidz ?

24 disks, 2 controllers. You could create a mirrored pool of 12 vdevs, e.g. zpool create tank mirror c0t0d0 c1t1d0 zpool add tank mirror c0t1d0 c1t2d0 ... Alternating between the 2 controllers for each mirror so that when one controller fails, the pool would become degraded but still available.

Re: [zfs-discuss] ZFS percent busy vs zpool iostat

On Tue, 11 Jan 2011, Andy wrote: I am monitoring the percent busy, and the data in/out on the physical disks and I am seeing close to 100% busy often. Thats ok, these things can happen! ;). The thing I don't understand is why during these busy times that zpool iostat shows very low IO. During

Re: [zfs-discuss] Size of incremental stream

On Mon, Jan 10, 2011 at 2:40 PM, fred wrote: > Hello, > > I'm having a weird issue with my incremental setup. > > Here is the filesystem as it shows up with zfs list: > > NAME                                USED  AVAIL  REFER  MOUNTPOINT > Data/FS1                           771M  16.1T   116M  /Da

[zfs-discuss] ZFS percent busy vs zpool iostat

Hi, I've been looking at a performance issue on my system, its FreeBSD 8.1, zpool version 14 (hope Im allowed to ask about FreeBSD on here?!). Anyway I think its quite a general question. The pool contains a single 2 disk mirror, using 5k SATA drives. I am monitoring the percent busy, and th

[zfs-discuss] Disabling SUNWattr_ro and SUNWattr_rw

Hello, I was wondering if there is any way to disable the SUNWattr_ro and SUNWattr_rw file attributes in OpenSolaris. I am receiving some permission denied error messages assocaited with SUNWattr_ro on some files. It has been suggested that there is a way to disable them, or remove them, etc.

Re: [zfs-discuss] ZFS/NFS benchmarking - is this normal?

> So, my questions: > ... > 2) Are they ways to see if the L2ARC or ZIL are being utilised (and > how effectively)? Richard Elling has an excellent dtrace script (zilstat) to exactly answer how much activity (synchronous writes) the ZIL encounters. See link: http://www.richardelling.com/Home/

[zfs-discuss] zfs send & tape autoloaders?

I've used several tape autoloaders during my professional life. I recall that we can use ufsdump or tar or dd with at least some autoloaders where the autoloader can be set to automatically eject a tape when it's full & load the next one. Has always worked OK whenever I tried it. I'm planni

[zfs-discuss] ZFS/NFS benchmarking - is this normal?

Hi I have installed Nexenta Community Edition as a virtual storage appliance in my home lab server. The server is running VMware ESXi 4.1 on an HP ML110 G5 server with 2x1TB SATA disks and a 60GB SSD. All three disks are configured as datastores which hold the VM disks. The server also h

Re: [zfs-discuss] (Fletcher+Verification) versus (Sha256+No Verification)

> From: Lassi Tuura [mailto:l...@cern.ch] > > bc -l < scale=150 > define bday(n, h) { return 1 - e(-(n^2)/(2*h)); } > bday(2^35, 2^256) > bday(2^35, 2^256) * 10^57 > EOF > > Basically, ~5.1 * 10^-57. > > Seems your number was correct, although I am not sure how you arrived at > it. The number w

Re: [zfs-discuss] (Fletcher+Verification) versus (Sha256+No Verification)

Hey there, >> ~= 5.1E-57 > > Bah. My math is wrong. I was never very good at P&S. I'll ask someone at > work tomorrow to look at it and show me the folly. Wikipedia has it right, > but I can't evaluate numbers to the few-hundredth power in any calculator > that I have handy. bc -l