Re: Very low disk performance Highpoint 1820a
Eric Anderson wrote: I'm using fiber channel SATA, and I get 2x write as I do read, which doesn't make sense to me. What kind of write speeds do you get? My tiny brain tells me that reads should be faster than writes with a RAID5. I'm seeing similar sequential performance on RELENG_5_3 and RELENG_5_4 on dual-Xeons using 3ware controllers so it does not seem to be a driver issue but somewhere else in the architechture. Depending on the array configuration, 40-60MB/s reads and 100-160MB/s writes. The write performance is as expected but the read performance should be above the write performance. Pete ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: 4M page size
Scott wrote: Petri Helenius wrote: FreeBSD/i386 uses 4MB pages to hold the kernel text and data, but there is no way (to my knowledge) to ask the pmap layer for a 4MB page after that either from the kernel or from userland. However, it's also my understanding that most non-Xeon CPUs only have a 4kb TLB, and 4MB pages are just broken down into 4kb chunks for it. Does this hold true for amd64 too? And what does happen to the page size if the memory is mapped to userland? (probably 4k?) (I assume mmap does 4k, not 4M pages?) Pete ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to [EMAIL PROTECTED]
4M page size
Is there a way currently to utilize 4M page size with FreeBSD for large data set programs (to optimize TLB misses)? Pete ___ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: 20TB Storage System (fsck????)
Max Clark wrote: Ohh, that's an interesting snag. I was under the impression that 5.x w/ PAE could address more than 4GB of Ram. It does. However as long as a pointer is 32 bits, your address space for a process is maxed out at 4G which translates to about 2.5G user after kernel and other things have taken their toll. If fsck requires 700K for each 1GB of Disk, we are talking about 7GB of Ram for 10TB of disk. Is this correct? Will PAE not function correctly to give me 8GB of Ram? To check 10TB of disk? PAE functions correctly but does not provide for 7G address space. Is there anyway to bypass this requirement and split fsck into smaller chunks? Being able to fsck my disk is kinda important. Yes, you do that by splitting up the filesystem to smaller filesystems. Kind of obvious? I have zero experience with either itanium or opteron. What is the current status of support for these processors in FreeBSD? What would the preferred CPU be? Will there be PCI cards that I would not be able to use in either of these systems? I´m personally biased towards the Opteron, but that´s more based on that it makes more sense than their technical merits so far (because neither has too much). Both CPU´s should work fine with 5.2 according to the TODO list. Meanwhile I suggest you play with the number of inodes on the 10TB filesystem and see how that affects the memory usage. Pete ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: 20TB Storage System
Geoff Buckingham wrote: - This is a big problem (no pun intended), my smallest requirement is still 5TB... what would you recommend? The smallest file on the storage will be 500MB. If you files are all going this large I imagine you should look carefully at what you do with inodes, block and cluster sizes fsck problem should be gone with less inodes and less blocks since if I read the code correctly, memory is consumed according to used inodes and blocks so having like 2 inodes and 64k blocks should allow you to build 5-20T filesystem and actually fsck them. Pete ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: 20TB Storage System
Poul-Henning Kamp wrote: I am not sure I would advocate 64k blocks yet. Good to know, I have stuck with 16k so far due to the fact that our database has pagesize of 16k and I found little benefit tuning that. (but it´s completely different application) I tend to stick with 32k block, 4k fragment myself. This is a problem which is in the cross-hairs for 6.x You have any insight into the fsck memory consumption? I remember getting myself saved quite a long time ago by reducing the number of inodes. Pete ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: FW: 20TB Storage System
Poul-Henning Kamp wrote: 2) What is the maximum size of a filesystem that I can present to the host OS using vinum/ccd? Am I limited anywhere that I am not aware of? Good question, I'm not sure we currently know the exact barrier. Just make sure you run UFS2, which is the default on -CURRENT because UFS1 has a 1TB limit. 3) Could I put all 20TB on one system, or will I need two to sustain the IO required? Spreading it will give you more I/O bandwidth. Can you say why? Usually putting more spindles into one pile gives you more I/O, unless you have very evenly distributed sequential access in pattern you can predict in advance. Pete ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to [EMAIL PROTECTED]
