Hi Virginia! > We are running LDM 6.4.2 with a 2000M Queue on a system with 3.8GB and 23G > available in /home/ldm/data > > Can we increase the Q size to 4000M > We are not using /dev/shm for /home/ldm/data/ldm .pq It is just a regular > file. > > Developer said: > I have already tried to increased the queue-size but got an "Illegal size" > error. > and also changed Q size in ldmadmin.pl.conf You've actually asked two questions. The first one is whether or not the size of the queue can be greater than the amount of physical memory. While we recommend that you have sufficient physical memory to contain the entire queue (for performance reasons) we have successfully run instances of the LDM in which this wasn't true. I'm afraid that we can't predict what will happen in your particular case, however, because it depends on too many variables. If the system isn't operationally critical, then I suggest that you try it and see (after accumulating sufficient metrics so that you'll know if there's a problem, of course). The second question is why you got an "Illegal size" error when you tried to increase the queue-size to 4 GB. This is, undoubtedly, because the type "off_t" -- which is used to specify offsets in the mmap() system call -- is 32 bits in length rather than 64 (a 32-bit off_t can't specify all possible offsets into a 4 GB file). Beginning with LDM version 6.9.8, the building step attempts to maximize this "programming environment" constraint. You could try a later version of the LDM or try building the version you have on a 64-bit system. The output of the configure(1) script will tell you if you succeeded. If you do upgrade to a later version, then be sure to read carefully the CHANGE_LOG file. > Here is our system memory and disk: > > > $ free > total used free shared > buffers cached > Mem: 3986384 3962304 24080 0 203652 3396300 > -/+ buffers/cache: 362352 3624032 > Swap: 3068372 0 3068372 > > $ df -h > Filesystem Size Used Avail Use% Mounted on > /dev/sda8 981M 342M 590M 37% / > /dev/sda2 99M 26M 69M 27% /boot > /dev/sda9 44G 19G 23G 45% /home > none 2.0G 0 2.0G 0% /dev/shm > /dev/sda7 981M 17M 915M 2% /tmp > /dev/sda5 9.7G 1.5G 7.7G 17% /usr > /dev/sda3 9.7G 380M 8.8G 5% /var > > tgp48 current Q use > $ pqmon -i 5 > Jul 27 13:59:39 pqmon NOTE: Starting Up (25470) > Jul 27 13: pqmon NOTE: nprods nfree nempty nbytes > maxprods maxfree minempty maxext age > > > Jul 27 13:59:44 pqmon NOTE: 45248 286 442747 1998778440 417495 > 477 70785 86472 2242 > Jul 27 13:59:49 pqmon NOTE: 45259 305 442717 1997955432 417495 > 477 70785 84848 2243 > Jul 27 13:59:54 pqmon NOTE: 45233 311 442737 1996617864 417495 > 477 70785 163520 2241 > Jul 27 13:59:59 pqmon NOTE: 45266 306 442709 1997801688 417495 > 477 70785 161312 2243 > Jul 27 14:00:04 pqmon NOTE: 45278 304 442699 1997952512 417495 > 477 70785 116808 2243 Regards, Steve Emmerson Ticket Details =================== Ticket ID: QYR-744357 Department: Support LDM Priority: Normal Status: Closed
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