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Jul
13
comment Should I disable swap file if I have lots of RAM or should I move it to a virtual RAM drive?
I realized what was riling me about all this is that one side seems to be saying "pagefiles never do anything but good" and the other side is "pagefiles are terrible" and then people get entrenched on one side or the other. The "truth" is that in some cases they're very useful and even crash-preventing and in other cases they are not needed and can actually cause performance to decrease. I'm happy with that as my final statement regardless. Live long and prosper, @David Schwartz.
Jul
13
comment Should I disable swap file if I have lots of RAM or should I move it to a virtual RAM drive?
I just don't like hearing that "pagefiles are magic so don't turn them off or you'll be sorry" when I know that under many common circumstances that you can turn them off, and safely see an improvement in performance because you are no longer increasing disk I/O by 100% or higher whenever the MMS wants to do something. All I want to hear from the people on the other side of this debate is "yes, there are circumstances where you can turn them off and reduce disk I/O which can result in thrashing". I'm not saying pagefiles are always bad, maybe you can say that they're not always necessary.
Jul
13
comment Should I disable swap file if I have lots of RAM or should I move it to a virtual RAM drive?
I get that MMS designers might be preparing for some sudden worst-case memory allocation request, but I don't understand why the pagefile had to be so frequently written/read during the hours/days/years of use when the running tasks asked for a small fraction of RAM. I'm not saying we don't need pagefiles, I'm just saying on a scale of zero to perfect, this particular MMS fell short enough of perfect that I (and from what I can tell many others) got significantly faster hard disk I/O with no negative consequences by disabling the pagefile.
Jul
13
comment Should I disable swap file if I have lots of RAM or should I move it to a virtual RAM drive?
I didn't say that the MMS should write the page file the instant before it runs out of RAM, I said "until it was actually needed", and my point is that it should not be needed if you've got a very large amount of RAM and you're using programs that only ASK FOR a fraction of that. Yet Windows (at least XP, the last time I ran Windows with a pagefile) would be reading/writing the pagefile enough to cause thrashing even if only 10%-20% of the RAM was being used.
Jul
12
comment Should I disable swap file if I have lots of RAM or should I move it to a virtual RAM drive?
I do agree that a system with a pagefile doesn't HAVE to be thrashy - I just know from experience that with every version of Windows I have used it IS more thrashy, because Windows is reading/writing the pagefile even when it's only using 10% of the available RAM. No one would be arguing with you if the system didn't use a pagefile until it was actually needed (I believe linux is a lot closer to that if not already there). That would be a great thing. But, at least with Windows, that's not how it works.
Jul
12
comment Should I disable swap file if I have lots of RAM or should I move it to a virtual RAM drive?
@DavidSchwartz 'Saying "pagefiles can cause thrashing" is equivalent to saying that the memory management system is terribly, terribly broken.' I'd say the MMS you're describing IS terribly broken. The only universe in which a system with 4GB RAM and a 4GB pagefile is more reliable and less thrashy than a system with 64GB and no pagefile is a universe where the memory management system is terribly, terribly broken.
Jul
10
comment Should I disable swap file if I have lots of RAM or should I move it to a virtual RAM drive?
The only acceptable reason to say that everyone has to use a pagefile all the time regardless of the amount of RAM they have and how they use use their PC would be if the memory management system was terribly, terribly broken. Does someone running Win8 with 4GB RAM need a pagefile? Absolutely. Does someone running Win8 with 64GB RAM need a pagefile? Only if they are doing massive things that use more than the 4GB - 8GB that most users use. And of course pagefiles can cause thrashing. How can people even argue these points?
Jul
10
comment Should I disable swap file if I have lots of RAM or should I move it to a virtual RAM drive?
@DavidSchwartz I really don't understand why people are so vehemently pro-pagefile, when common sense (and actual experience) indicates it works fine. You're analogy "That's like saying you don't have to worry about money because you have lots of checks in your checkbook" is not correct. The analogy is that you were getting along fine on $50,000/year and you win $10M. You no longer have to worry about money if you keep reasonably close to the same lifestyle. If all you want to do is play World of Warcraft and surf the web, I'm certain you can do that without a pagefile on a 64GB machine.
Apr
23
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Feb
22
comment Can dd be used to copy an SSD with an OS?
I do this all the time between an SSD and a larger hard drive (keeping the same size partition as the SSD) and have never had to re-GRUB. The disks are exact duplicates including UUIDs. Of course, I'm assuming you're copying the entire drive, not just a partition (as mentioned above).
Oct
28
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Jun
18
comment Multiple disk controller cards and RAID1
And yes, btrfs has a RAID10 mode that you could make with 2 drives (you could even make it with 1 drive and 4 partitions), but with only 2 drives I'm not sure you could see a speed benefit and a redundancy benefit simultaneously. Seems like RAID1 with 2 drives would give you the same performance and redundancy as RAID10 with two drives...
Jun
18
comment Multiple disk controller cards and RAID1
This might be a bad assumption, but I'm assuming that for SATA2 interfaces and above and for rotating media (not SSDs), the I/O speed is largely limited by the drive speed - 3Gb/s = 300MB/s = more than twice as much as I've ever seen a HDD sustain. And small data bursts are severely limited by seek time. So HDD matching would be more important than controller matching. But you're right that experimenting is likely the only way to know for sure for a given configuration.
Jun
16
comment Multiple disk controller cards and RAID1
Thanks for the quick response, but this is a btrfs RAID array - so it's 100% software-based. That means you can achieve RAID with one drive attached to each controller, and the RAID options of the controllers don't matter, since the controllers are functioning as single-device controllers, not RAID controllers.