The genotype data for all 60 samples from consists of 23 .vcf.gz files with a total of 142G. Because of the size of data, it can be slow to import all these files into variant tools. Depending on your computing environment, you can

import all files together

The most straightforward method is to import all files together:

mkdir p1000g_all
cd p1000g_all
vtools init p1000g_all
vtools admin --set_runtime_option "temp_dir=/Volumes/AnotherDisk/tmp/p1000g_all"
vtools admin --set_runtime_option 'sqlite_pragma=synchronous=OFF,journal_mode=MEMORY'
vtools import /path/to/ALL.chr*.vcf.gz -j8 --build hg19
vtools admin --merge_samples

Command vtools admin --merge_samples is needed because genotypes for these samples are imported chromosome by chromosome, and appear as multiple samples with same names.

import data chromosome by chromosome into subprojects

If you have a cluster system to spread the workload, you could create multiple projects and import genotypes chromosome by chromosome. That is to say, for chromosome 1, ..., 22 and X, you can create bash scripts such as

chr=1
mkdir p1000g_$chr
cd p1000g_$chr
vtools init p1000g_$chr -f
vtools admin --set_runtime_option "temp_dir=/Volumes/AnotherDisk/tmp/p1000g_$chr"
vtools admin --set_runtime_option 'sqlite_pragma=synchronous=OFF,journal_mode=MEMORY'
vtools import /path/to/ALL.chr${chr}.phase1_release_v3.20101123.snps_indels_svs.genotypes.vcf.gz -j4 --build hg19

After all jobs are completed, you can merge the projects using command. The project and sample merge steps can be slow (about 1 day), but this method leaves 23 subprojects, which are much smaller than the master project and can be useful if you are only interested in data on a particular chromosome.

mkdir p1000g_merged
cd p1000g_merged
vtools init p1000g_merged --children ../p1000g_* -j8
vtools admin --merge_samples

merge vcf files before importing

To avoid merging samples, you could merge the vcf files using vcftools before importing them

mkdir p1000g_single
cd p1000g_single
vcf-concat /path/to/ALL.chr*.vcf.gz > ALL.vcf
vtools admin --set_runtime_option "temp_dir=/Volumes/AnotherDisk/tmp/p1000g_all"
vtools admin --set_runtime_option 'sqlite_pragma=synchronous=OFF,journal_mode=MEMORY'
vtools import ALL.vcf -j8 --build hg19

This appears to be the most efficient method to import this dataset.